I feel like there is a lot of the 'old guard' who could snap their fingers and get 10 or 20 people to sign for a game.
But understanding what it is that makes people want to do that and what creates a brand of fun that keeps players coming back may be worth a conversation. MU does have a player draw for its people but that started with the games it hosted and the experiences it created. Things like turbos were even popular although their site was terrible for hosting them with issues like refreshing pages jumping post, just because the player base was there.
Regular community melt downs over staff abuses were common yet they had a popular enough platform that their users accepted such bad moderation to the point the last one I saw was excused as 'Its been a while sense the last meltdown so staff are doing better.'
Honestly replicating what they created would not be hard. It could be as simple as making something cool and inviting a bunch of communities to play it. If I was going to try to do it I would start by hosting a series of external cross community games on other peoples sites but then inviting those sites to some event. Unless someone wanted to replicate the 'place to be' trendy sort of attitude and they would probably quickly find a lot of people walking away. Even before I ever had issues with MU that kept me on the edges of that community despite creating a lot of things I held in very high regard.
Reach out to Superjack if you want to hear about how the planned '3 game' cross community interaction went back in the day. He also had some cool stuff for voice/video mafia games that I would like to see become a thing again. The Liers Club has some badass people and a super cool platform if we could create a player draw and coordinate with them..
Intellectual growth comes from discussions, not arguments. If you are unwilling to change your position and hear the other persons side you are closed minded and wasting your time.
If you can not clearly explain what the other sides reasoning is you can not disagree with their position because you do not understand it.