Your comment just made me realize I did a kind of GOG holiday sale shopping spree this year after having not done a steam holiday sale purchase in like a decade.

And the majority of it was having cheap easy drm-free access to some very good and very old games. Like yeah I know I have my ISO of the TIE Fighter collector's cd-rom somewhere around here, but if I can permanently have legit drm-free access to all versions of the game for just a few dollars, then supporting the business enabling that is a no brainer.

I think that both GOG and Itch.io not only rely on their strenghts, but has their own niche market to cover, so they don't directly compete but complete each other in the whole gaming scene and they can easily coexist. That's Epic who wants to get a slice of general gaming pie Steam eats.

Yeah. GoG and Humble (as well as many MUCH smaller stores) have very much criticized the de facto Valve monopoly over the years (... decades?). As have many devs who have criticized just how much of a percentage Valve takes (and how they reduce that for the big games). They just generally are smart enough to say it VERY obliquely because they know they don't want to antagonize a rabid userbase.

Epic... Epic increasingly are poised to "not need" PC gamers as it were. Fortnite is its own platform and Unreal Engine is increasingly used by film and industry. So they are much more willing to criticize Valve (and only occasionally remember EGS is sort of a thing...) which... tends to highlight why nobody else does.