MOBA niche, MOBA not only dominated pc online gamers base but also whole pc gamers base. According to some statics for a particular time League of Legends holds 21% market share of all online pc gaming something that even come close to it 6% or something like that is another MOBA, So u got how MOBA's are dominating online pc gaming base.

Maybe MOBA games popular for mobile games too, that that games u see dominating miobile zoner for now, for example clash of clans, once this kind of base building and strategy games was huge success on PC. Now u probably got y this hike with call of champions from STS.

There will be always complain about PvP and it's fairness, but let just think, for example in PL, u can gang banged by 3 players and the other two teammates are just chatting and even blaming u for not apparently no proper reason but here u get some players to play or even bots, spwning is not really possible in coc.