While I generally agree with what you are saying, the two statements aren't completely contradictory. A company that feels they will lose sales to piracy may avoid releasing a DRM-free copy of their game until they have sold about as many copies as they feel they are going to sell. Likewise, it may be that after a game has been widely pirated, or the DRM protections broken, a developer feels there isn't any purpose in not releasing a DRM-free version of their game.

This is just me spitballing, I don't know for a fact that the above represents what developers are thinking.

I think lost sales due to piracy is just part of the equations these companies have to consider. If actual sales on a platform (GOG for instance) far outweigh lost sales due to piracy, it's probably worth it to release on that platform. Completely made up example: If I can sell 1000 units on Steam with 0 lost to piracy or 2000 on GOG with an additional 1000 lost to piracy I'd probably choose GOG for those extra 1000 sales. Assuming the same take and costs of support on Steam and GOG. If you an in another store like Epic or something in-house like Uplay, I really think its the same idea you're just moving the slider one way or another. I have no idea what these numbers are but the big AAA publishers likely have finance teams that make models for exactly this kind of thing.

We need to know how much does the GOG version impact sales for games released at the same time here and on Steam, to give an answer to the OP question. I mean, at this point, we don't even know how much of a competitor is GOG for Steam.

This topic may be of interest to you:
https://www.gog.com/forum/general_archive/steam_vs_gog_vs_direct_sales_detailed_breakdown_for_defenders_quest

The article is old, but Witcher 3 evidently sold better on GOG than Steam:
https://gamerant.com/the-witcher-3-gog-sales-410/

On the other hand, Witcher 2 sold many more copies on Steam (albeit this article is 7 years old):
https://www.pcgamer.com/gog-release-witcher-2-sales-stats-steam-dominates-all-competitors-combined/

Unfortunately not a lot of publishers/developers like releasing sales numbers, I suppose they don't see any value in it. So getting an idea of how GOG's numbers stack up to Steam (or any other competitor) is pretty hard.

All the missing big titles will be released.

...once Windows 7-10 are no longer supported and you need some sort of Win-Box program to load up old 32x or 64x bit games (when we're all laser scanned and working overtime in the death camps for the Skynet terminator bots).

Those are best-scenario-cases, unfortunately, they can't be fully representative of the true GOG/Steam day one split. I mean, 99% of the games sell waaaaaay less on GOG than they do on Steam, that's pretty obvious, because Steam is a much bigger platform. What we need to know to have the full picture is how much bigger it is.

Sure it's possible: GOG could agree to add DRM to their games.

Or, they could drastically reduce the cut they take from the current 30%.

Other than those things, unfortunately I doubt there is much that can be done.

Although just like Fallout 3 and Fallout 76, Fallout 4 is awful. I have no idea why so many people want bad games like Fallout 4 here.

I know how to make big games... just leave EVERYTHING uncompressed. There, solved!

It's impossible so GOG will die and we will crie

So much for my hopes for the Total War series. I think I'll just cry in the corner now.

It can't hurt to try to let publishers know you want the games here (social media like Twitter and forums). and of course, vote on the wishlist.