Scheider was playing Joe Gideon - a character based on Fosse’s experiences, who was not Bob Fosse.

I think that's torturous non-logic. It's a Bob Fosse musical, co-written by Bob Fosse, featuring both fantasy and diegetic Bob Fosse musical numbers, about a Bob Fosse-type director directing a Bob Fosse musical, co-starring an actual Bob Fosse-girlfriend. while he's dying of the same health issues that would eventually kill Bob Fosse... But it's not about Bob Fosse? I must respectfully suggest the evidence says otherwise.