The player base ISN’T the gate that decides whether or not other players can access content. The player base does get to decide who they play with.
Make your own group, make friends, join a guild - all solutions to this issue.
I know easier to try and get papa blizzard to force people to accept you but they aren’t going to do that with all content. If you want that kind of content LFR and Heroic dungeons await you.
And you are wrong here too. I don’t do mythic plus dungeons outside of ones done with my guild. So no I am not benefitting from the current system because I am not part of the pugging scene.