Citation needed. There's been plenty of developer comments about selling well there. I know you think they're lying, because it gives you good feels, but I doubt it. Exclusives have always worked with video games, it's why there's more than one console. The trick is turning those exclusives into repeat customers, and I don't see any way in which they're doing that.
We about know what the Maximum Sales volume for a Third-party game is, Borderlands 3 was the most popular game released on the "Epic Games Store" and apparently broke 2 million, everything else including Metro: Exodus and HITMAN 3 is probably lingering around or below the 1 million mark:
This is the number for a moderately successful Indie game on Steam. Even something like Crusader Kings III probably beats that in number and even Early Access games like "Baldur's Gate 3" can do those numbers. Aside from Fortnite there is no other "Breakout Hit" on the Epic Games Store. There is nothing like Destiny 2, Playerunknown Battlegrounds, Cyberpunk 2077, GTA V, Among Us, Fall Guys, Monster Hunter: World, Rainbow Six: Siege, Doom Eternal etc. on there.
Chances are there also cannot be without immense growth first, which seems to not be happening. So if you have a game like that and take the EGS money you are essentially crippling your Launch and very important Year1 where it can become a Breakout Hit or Streaming Sensation or whatever for thirty pieces of silver, dooming your game to be a million Seller at best and maybe get some people interested after the "Excl000sive" period is over. If you lack any confidence in your product being successful maybe it's worth it, otherwise it's very stupid.
The most popular third-party game on EGS sold less than Valve's VR-only game.