The engine license isn't really a hidden cost, everyone in game dev knows about it and it gets waived or reduced for sales on EGS. Also the first million dollars per year is royalty free for each game. And it's only for Unreal Engine games and was there before the shitty store.

Their engine is actually a REALLY good deal for a lot of studios. Doing everything it offers in Godot would cost a ridiculous amount of extra dev time for a lot of cases