https://raider.io/mythic-plus-rankin...xMythicLevel=3
This is a link to the amount of unique characters that have completed +2 and +3 keys in SL so far. We are talking about several millions.
I must disappoint the majority in this thread, which by the way is a tiny majority in-game, that Blizzard will not remove the most successful addition to the game since the introduction of LFR.
Mythic + is made for and used by all players in wow, from the most casual to the most hardcore, from the least skilled to the most skilled. It is for everybody and done by everybody.
The people complaining in this thread should just realize this content doesn't suit their fun, just as some people don't find pvp fun, just as some people don't find pet battles fun etc. etc.