That is an excellent point. It’s easy to look at the decline in WoW subscribers and blame x, y and z change (that poster doesn’t personally like). However, the gaming industry has changed an awful lot since the peak of WoW in 2010 and maybe the reason for the decline is simply that there’s just far more competition.
League of Legends was launched in 2009 and has become very, very popular in China. The MMO PvP gameplay modelled on one (non-RPG) part of WoW is probably a big reason why China has far few WoW subscribers than in 2010. More recently, there’s Fortnite as the cool game for the nerdy kids to play (which was once WoW). The tech has changed too - the iPad was released in 2010 and opened up a whole new level of competition in the gaming industry.
WoW is a game from a bygone era, in that it’s so complex and has so many different aspects to it whereas the majority of current successes are pretty straight-forward. You don’t need to gear up and grind rep to play Rocket League competitively! Blizzard are making a real go of keeping it going in its traditional format, as they could have either cut their losses or rebooted the game as a different type of thing. Most games these days are very accessible and very easy to play at a low level. Can we really blame Blizzard for making changes to WoW that make it more accessible and easier to play at a low level?