Yes, I have been taught both engines at degree level. You keep talking about these engine bugs, but could you give me some specific examples of the some of the bugs in these games, just so I can get an idea of what youíre talking about? The fact that you previously stated that Pokemon Go's server issues are the result of Unity's engine makes me think you don't really understand. As I've said before the bugs are almost never due to the engine, but instead bugs in the game itself. I could give you examples of Unreal games which are riddled with bugs, but itís purely down to the games code and not Unreal. I mean youíve got 6 years of game development experience, surely you understand this?
Correlation does not equal causation. Just because bad games are made with the engine doesnít make the engine bad. Watch this video
Do you honestly believe that YouTubers and people who play games have more knowledge of game engines the developers? I'd have to disagree.
Like pretty much everything it depends on the game itself. Youíre absolutely right about memory management and it can be a big deal, but the benefits are felt far less by smaller games. Unity is very lightweight compared to Unreal, something that mobile games feel the benefit from massively due to their limited processing power. This sums it up far better than I can.
Well to start on the bugs, Ori and the Blind Forest's Gino tree bug, Pokemon Go's gym bug where even after beating a gym, Doesn't change anything and would require you to beat it several times over, I could go on forever on known bugs like this. I'm not saying this is Unity Exclusive as I said before,I can also list crap ton of engine bugs from Unreal and Cry, all games eventually get bugs. It's just Unity is far more likely to not land on that rock when your character jumps and read it as a Collison or not always 100% likely to make an Enemy NPC Chase you correctly. Or possibly do something that requires you to restart your game. I'm not saying whatsoever you don't get these in Unreal and Cry and other engines, But you're likelihood of Unity making a small goof and not reading code correctly time to time is just a higher chance than that of other engines. Which does not make it a bad engine, It just requires far more maintenance to keep bugs out of the game when the engine isn't doing something right in some fashion.
There is bad games made in every game engine, That's not exactly the issue, The issue is not the game itself but rather will the engine always do what It is scripted to do if you wanted to check out a menu or something. Which just requires more work than it actually needed.
Many of these YouTubers and ordinary gamers do infact have a lot of knowledge on game engines, A lot actually, Especially when they experience playing so many games made from a wide variety of game developers, Especially many big YouTubers often themselves follow large amounts of game developers and know them extremely well, Examples being Jacksepticeye who knew Naughty Dog's interior design for their games was massively amped up in Uncharted 4 than their previous games made by them, Markiplier also states how various game developers also made big improvements in their games on many occasions as well, You underestimate severely how much people know of games and their development. Of course not the average mellow laid back gamer knows everything, But bigger gaming people who take interest in these things and follow so many game developers and actually take note of what they do know a lot more then you give them credit for.
If you're making a massive game, Regardless of the engine you're using. It's more than likely going to face issues, But in terms of Unity or Unreal, It wouldn't matter, Many engines can make good Mobile games, Havok is a fairly good engine that made Gangstar Vegas, Which is close to being like GTA for mobile.
Most game engines are fine for Mobile, But when we talk about Mobile development it doesn't make much of a difference whatsoever if the developer decides to make terrible memory management, Unreal is a bit more heavier with the APK packaging yeah, But with C++ it doesn't make it much more different than anything else, I've never experienced a single issue in my experience for performance for Unity and Unreal and other engines I made Mobile development, I mean hell this game below which I been making for the past few years or so, Which i made copies for on Unity and Unreal doesn't have much of any performance issue for when me and my friends play on it(It's a private game, Not public) and this game has a lot to it. Never any performance issues from either Unity or Unreal when on either engine when we was on our mobile devices playing it, Same goes for for anything else I made. As long as you're not trying to put Black Ops or Call of Duty on your phone and you're not recklessly adding multiple high performance consuming things,Then regardless of the engine it'll be fine.