Yeah, but people who prefer to play solo will also get a chance to participate in M+. Will get a chance to the Great Vault; to M+ gear. Like Torghast - we can do it solo and in a group. It doesn’t take anything away from 5 man dungeons, only adds to it.
It’s is also beneficial for those who play specs that are not chosen often in 5 man dungeons. In every expac there are a few specs like that. It gives them a chance to play end game content and gear up, maybe not at the same rate a 5 man will but yeah, they’ll get there.