I also loved "Dreamgirls", "Disney on Ice" music and all. It's a Broadway musical. What did you expect it to sound like, real Supremes songs? "Chicago" sounds next-to-nothing like authentic 1928 jazz music. At least "Dreamgirls" makes a halfway decent attempt at charting R&B music from doo-wop to disco (I don't think I'll ever again see a film with a song done in the style of Motown producer Jeffery Bowen ever again)
Incidentally, real Supremes songs had a tendency to sound even more like "Disney on Ice" than anything in "Dreamgirls". Anyone who is actually familiar with the Supremes' catalog outside of what gets played over the Muzak speakers in Red Lobster can tell you that.