There are multiple reasons for this dilemma you're experiencing. To pick just a few is generalizing. What I'm most passionate about and point to the most is the rewards system flaws. I believe the game is still fun, still merits skill, still plays a "similar" meta as it always had in 3s.
But participation is down to an all time low. Stats websites look at a collapsed ladder and point to the horrific numbers. Yet, mythic+ is seeing more player participation than raiding and all forms of pvp
combined.
If you've participated in m+, you know the content isn't new. A few runs, popular strats emerged each season, the same skins/encounters week-after-week. What's so special about m+? Why is it the number 1 content engagement?
I believe gear.
If 3s rewarded gear, people looking for smaller group content would hop back in. If 3s rewarded gear, you'd have people on your friends list wanting to play. Even if gear was still irrelevant while doing pvp, players would crossover for it. Even if it was the current flawed "all gear lottery pool" we play with today was still in place, people would engage more if the ilevels of said random rewards were appropriate.
Appropriate rewards. Appropriate gear. I care so much about the perceived problem
I broadcast it to the community, even though I'd rather do anything else.