I don’t have the full story yet.
Sandy says:
They never really have distinguished themselves from YICC or Beth Jacob, the two shuls most similar in practice to MD’s Ashkenazi minyan. A lot of the regulars are guys who used to go to YICC or BJ, and either live closer to MD or are old buddies with Rabbi Elias (or their wives are).
One unsung hero of Mogen David’s Ashkenazi minyan is their Torah reader, Aaron Breitbart. Aaron is about as self-deprecating a fellow as you’d ever meet, with a great sense of humor backed up by an academic’s intellect.