MMORPG should be left for the kids with enough spare time to raid 4+ hours a day. Many would disagree, but from my experience it is friends that keep you coming back every day and you can't make them this days with all this casual queues and playing few hours a week.
4 hours a day raiding is bullshit. Most guilds raid 12 hours or so a week. The very competitive guilds traditionally only raid a lot in first 2-3 weeks (w/first week being split farm). They take time off work/uni then. Sco, for example, from best guild Method, is a Scottish fellow who worked in finance for various years (he's now full time earning money with his guild).
With Legion, its the stuff outside of raiding which takes up a lot of time. The endless grind of artifact power, legendaries, and rare epic upgrades.
It is possible to play casual though. I raid 6 hours a week (less than 1 hour a day), and out of 10 we're only 2 bosses behind on Mythic (the toughest difficult). With the last boss being exceptionally hard.
Never mind that issues with meaningless grinding are shared by both single-player CRPGS and MMORPGS. (And leveling the whole world along with your PC is a very unsatisfying solution).
WOW lost a lot of luster when 40 mans got retired...
My best memories of WoW raids were the drunken Friday night guild runs through UBRS. We knew the bosses well enough so that they didn't really require any effort or co-ordination and we were free to chat and talk crap amongst ourselves. Our tank usually got so drunk by the time we got to the end that we were glad the hunter had to kite the boss away.
I had to stop playing because the time commitment required to be an active member of the raid group got ridiculous. Literally every evening and most of every weekend. If you couldn't do that then you couldn't compete. Stuff that, this is a hobby not a job.