No kidding. How many good game franchises have been wrecked by seeking to become the next WOW?
One fact that is forgotten is a not all D&D players are MMORPG players. In fact, most of the people I have played with no not like MMO. Otherwise, would the two D&D MMOs be bigger then they are?
It is easy to get carried away here. There have been two
significant contractions in terms of the player base -- mostly in people by-passing even entering the game (as opposed to leaving it), but it's happened
twice.
The first was M:TG. That new game sucked out the wallets of players and many kids who might have played AD&D instead played M:TG and then moved on to something else. That disruption in player acquisition was fatal to a brand that was already wounded. AD&D died -- and the makers of M:TG ended up buying it.
The second occurred vaguely in 2006 through 2010, at WoW's height. There were a LOT of gaming groups that died or were dissolved at that time as players moved to WoW. There were DOZENS of those threads here on ENWorld at the time, some with MANY posts. Many others, who might have become D&D players? They simply did not. They were too busy playing WoW. What effect this had on 4th Ed? We'll never really know, but it certainly inspired aspects of its design. And in the end, 4e didn't turn out well for anybody.
Indeed, WoW was large enough at its height that it
sucked the very life out of the rest of the computer games business (except for WoW itself). Retailing of all computer games came to an end in 2008 in virtually every retail point of sale in North America and most of Western Europe. It took another ~18 months and Steam to save that industry. (See "the Domedness of PC Gaming" threads from that era). Many computer game developers went under because of it and it changed the entire computer game publishing industry,
from top to bottom. Those changes persist to this very day.
You are projecting your own social circle and personal experiences here in a way that is unwarranted and inaccurate.
tl;dr: WoW was disruptive AF.