Anyhow about your examples, the first 2 are basically dead and the other 2 are too much mainstream games to count for anything, PUBG is falling in Fortnite's shadow and Ark isn't as hot after the whole debacle about it's DLC. Of course they're not stupid enough to waste time on the games when they've already made their money off of them.
Not much pointing arguing with a person who only picks some of the worst run games on UE4 to make an example of in my opinion. All of which are 100% at the fault of the developers and not the engine.
UE4 also is used by Fortnite, Gears 4, Squad, and Hellblade. All of which run very well and are all good games. 3 of the 4 have solid looking graphics and Fortnite literally runs on anything.
In my opinion, using UE4 is a plus considering how versatile and accessible the engine is. Alteast with that we know the engine won't be a steaming pile of broken shit.