I said nothing about what is meaningful or what isn't.
What I am saying is that Blizzard created M+ to satisfy those who want something other than raiding.
But ultimately that play style, if taken to its furthest possible conclusion is nothing more than Diablo WOW.
Meaning theoretically infinite difficulties with theoretically infinite rewards. This is the path the game has toyed with since Legion.
However, some players don't want the game to become a Diablo style ARPG MMO and have been pushing back.
So yes, literally either it is A or B in terms of the long term future of the game.
You really can't have both and make everybody happy because if M+ has a top end "infinite" difficulty above raiding, raiders will complain.
And vice versa.
Blizzard is trying different things to balance things between the two but they mostly haven't worked out.
Island Expeditions and warfronts are a good example. Torghast is another try at infinite replay but without infinite rewards.