kvachu: mean seriously, it's too much of a steal.
No it's not. There is no such thing as a "steal" on GOG, nor on any other digital game store.
High discounts, like 80% or more, only ever come on old ancient games, and/or on games that have flopped terribly if they are newish games.
Discounts like that are a normal standard matter of course for video games. Videos games always drop in value as they get older.
So the "sale prices," even at high discounts like 80%, are the actual true real value of the games. No way they are actually really truly worth their alleged full MSRP many years after they have been released.
If those games were not discounted that highly, then almost nobody would ever buy them; therefore, it's not in the publishers'/devs'/GOG's interest to keep the prices high...which is the only reason why they don't.
That is to say, they aren't giving out high discounts in order to be "nice," or anything like that.
As for the the "free giveaways:" they are a marketing gimmick meant to promote & advertise the store giving away the games. They are not done out of the goodness of the store's heart because they have a great love for being charitable.
Although I do think GOG should not do giveaways, but for different reasons than what you are saying.
The real reason why GOG should not do giveaways is because they do not actually work at promoting/advertising GOG, nor bringing any new customers to GOG, nor bringing increased sales from old customers.
In other words, GOG's "free giveaways" do not have the intended promotional effects for GOG that are supposed to come with free giveaways, therefore it's not something that is worth doing for GOG.