It is a monopoly - they just don’t abuse it as much against their audience.
For developers it’s either take their 30% deal or just don’t sell your game because a lot of people only use steam.
Not even Cyberpunk or the Witcher could sell more on gog than on steam even though you knew that there the developers got 100% of the money spent. Gwent standalone flopped so hard on GOG that it had to be rereleased with limited features on steam and sold more there
People are just fundamentally lazy so it totally is a problem that you have one store with such a massive market share even if it’s very convenient for the end-user they can completely exploit their position against publishers.
Sure EPICs way of making games exclusive to their store is not elegant but without that no-one would choose that store over steam
The whole period before about behaving responsibility and using masks showed you all you needed to know about how responsible and interested in the general wellbeing most people were so it only made sense to not leave it up to chance with that.
And it’s not like anyone was forced - only other people were secured from coming in contact with irresponsible and self-centred people that couldn’t care less about them