Sega is the latest to abandon Steam. The competition from the Epic game store has been as much as a nuisance for those who have jumped in whole hog with Steam.
Epic also has the stigma of being backed by Tencent of China. Tencent however is an entertainment company and they are not a government enterprise. On the face of it, the Epic loader is the worst of them all.
A Total War Saga: TROY will be released August 13, 2020. Recall the howls of rage when Metro Exodus abruptly left Steam for Epic.
I agree that the fees from Valve/Steam are probably more than they should be. Steam probably runs afoul of Sherman among other laws. This is about the only legal basis to clean up the problem for everyone concerned. So far litigation from smaller studios has not been successful.
Sega was stiffed by Randy Pickford (Gearbox) back when he was contracted to develop Alien vs Predator but Pickford spent most of the money on Borderlands. So most likely Sega wants to find a safe place to sell their games. AvP has one of the shortest campaigns of any game I have in Steam.
Many gamers suspected that Sega would take Gearbox Software and Randy Pitchford to court over fraud and embezzlement charges, but according to an anonymous Sega employee, that may not happen due to contractual obligations. Given the problems and the lack of oversight its clear many mistakes were made.
Sega blamed Gearbox over the Aliens: Colonial Marines fiasco. Again the allegations of embezzlement are flying around. The game was a commercial failure.