Just looking at Twitch streaming and viewership alone, I say this isn't anywhere close to being true.
WoW is nearly always a top 8 game, currently with 71.4K. ESO lately has more often than not been below Final Fantasy and BDO. The only reason ESO is so high currently is 10K watching ESO Live stream.
If WoW dumped the mandatory monthly sub I'd jump on board with it. Actually, same with FF.