I think the primary reason that there are a lot of 1985 Pete Rose Red home jerseys is that Rose ordered extras to give away (new and unused) to all the people who were meeting with him during the runup to his record-breaking hit and wanted a hat, bat, jersey, etc.

I have heard that, after the 1985 season, some extras (maybe one or two dozen) were also sold to the public (for something like $100) at card shows by his friend and business associate Whitey Willenborg.