Doesn't Steam have a clause saying that prices can't be lower on other stores? At least I recall some indie devs who were asked why did they do the USD = EUR thing on GOG say that they used Steam's recommended pricing matrix and then they were required by contract to not have lower prices anywhere else.
If the free market would work the way its supporters claim it does, 20% would be humongous...

epic should try the drm free route, they have more resources than gog and might be able to make it work at a bigger scale. steam is poison and drm, it ruined pc gaming in a lot of ways.

From the Steamworks documentation available online, the general guideline appears to be "Don't give Steam store customers a worse deal than Steam key purchasers" without a lot of specifics. I couldn't find any formal price fixing rules other than Valve just asking that the Steam store eventually get comparable deals to those offered for keys. (I would guess that this partially has to do with the fact that Steam doesn't take a direct cut on keys but wants a chance to earn a commission as compensation for use of their infrastructure.) There are also anecdotes by devs stating that Steam doesn't allow prices on other stores to be lower, but at a glance I can't really find any substantial proof of that - at least in recent years. Everything in the documentation seems to be tied to Steam keys with no mention of competing stores. However, I would doubt that any of these rules are strictly enforced since keys are allowed in cheap game bundles.

So I guess I'm saying that those interested can search through the Steamworks documentation, read developer anecdotes, and draw their own conclusions. I can't really find any public-facing guidelines that are as strong as the claims by the indie devs that you mentioned, but I also can't say for certain that Steam doesn't have other more stringent guidelines that they just don't publish in their online documentation.

Epic has basically stated that they want to be the one-stop-shop for gaming that fosters competition. If that's the goal, I think that an interesting business angle for Epic would have been to be a "buy once, play anywhere" license broker where they set up reciprocal agreements between stores so you can pay a single fee to buy a game through EGS and obtain a license for the game at all major platforms. So if you want all of your games in the same place(s), then you could buy a game once from EGS and then get licenses on EGS, GOG, Steam, etc. without having to re-buy the game on each platform. (Think about something similar to a generalized version of GOG Connect.) That would be the ultimate freedom by maximizing player choice, and leveling the playing field substantially in terms of Steam dominance because there would be zero cost to move from one platform to another. Not sure how the finances on Epic's side would have to work in order to make it worth their while, but it would have probably been better idea than the money bonfire that they've been fueling for years now.

I know that "slippery slope" argument, but to me it just doesn't fly. It is similar as the older "GOG is giving up its principles by selling also newer games and allowing regional pricing, which means next they will add DRM to their games".

Like I said, the service that GOG offers over e.g. Steam is being officially DRM-free, offering DRM-free installers, regardless if one also uses Galaxy to play their GOG games.

Offering Early Access games and a client to make their use much more convenient for daily updates etc. does not contradict that extra service. GOG can still offer also the DRM-free installers, also for those Early Access games.

However, adding DRM to single-player games nullifies that DRM-free extra service, and contradicts it. Or, at least it would be totally meaningless to e.g. add Denuvo to the Galaxy-version of a game, and at the same time offer that same game as a Denuvo- and DRM-free offline installer.

So no, that slippery slope argument doesn't really work in this case.

Well, GoG got billions in "market value" because their mother company got many shareholders. However, the problem is... they have to keep those shareholders happy, else they will not keep their shares anymore, resulting into lack of capital. So, they are actually strongly bound to the things that actually work.

EGS got way more freedom because this company is almost entirely privately owned, so there are as good as no shareholders at all. It will not mean they are able to make eternal losses because at some point they will need some fresh capital going back into their pockets. Yet, they surely got way more freedom of taking certain risks... without the risk of a pretty harsh reaction from all those "shareholders":

I am not sure but, i think Valve is not supporting any competition and perhaps not even truly allowing it. They seem to use many methods in order to keep the competition at bay... guess this is almost certain.

A good number of games at Epic are already DRM-Free Lite. Though like Steam they don't advertise or promote that, and they would if they thought it worthwhile.

That said, I don't think DRM-Free is about resources as such, but it depends on what you mean by resources. If by resources you mean to be able to fix old games and make them work on latest OS, then perhaps. We'd probably see more releases of old games at GOG, if GOG had the devs to work on more old games.

As for other games, devs are not likely to be more willing to provide DRM-Free at Epic than they are at GOG ... at least for AAA and even AA games. DRM-Free is not beloved by most of the game developing community ... big end of town.

Steam also have a lot of games that are DRM-Free Lite.

DRM-Free probably doesn't even appeal to most gamers, certainly those who prefer Steam, which is the majority.

I think with epic resources they might be able to pay to get some titles to be drm free. there is a lot that care about drm free, they got forced to steam and some dont realize that its drm. also some dont go to pc and remain on console since they dont like steam due to it being drm.

In many cases Steam is simply cheaper, with almost hilarious price cuts on... in many terms insane prices. So the customers got in mind "thats a great deal and DRM i do not care, it will run and i have almost any friends there and the best launcher too", thats it. Good launcher, cheapest price ever and many "wannabe friend"...

For example Civ 6... on EGS it is full price, no price cut at all... but at least it seems DRM free. Same for Ghost of Tsushima, on Steam way cheaper if there is a sale (and in general way lower regional pricing for the regions affected) and on EGS always full price or very minor cut, but indeed... DRM free.

To me, it would be worth it to go EGS instead or GoG, but for the majority, price... launcher... and "friends" is all what counts.

However, i think GoG kinda is getting lesser of the high rated franchises in recent time because they simply can not afford it to "throw" a good offer to the publishers while EGS, in some cases... seems to be capable of, so the offer is good enough to become accepted in many cases... by the publishers. Sure, EGS will not make any cash out of those franchises (not even at higher prices, just to less customers), the whole point is to "lure" more customers toward this platform. Still, it is not working that great, even while handing out so many free games.

Even so, i enjoy to "balance out" stuff because to me i feel it is important to have some useful competition, at least 3 should be competing somehow. If every shop may have a comparable offer, i still may not get everything at the same place, but this is just me... the majority is not "social", instead mainly seeking for the very best personal benefit. I am lucky enough i even enjoy independence and some autarky, so those "other platforms" can even give me a benefit valuable to me, as a minority. Of course, most humans care less about those traits because they are genetically engineered to be sheeps, so they always want to be at the place "they can meet the most of the same".