What is the actual rationale behind the Broncos not going back to the classic uniform/logo full time?

I'll preface this by saying I've been a Bronco fan since 1984, but I don't live in Denver so I don't have my ear to the ground about the underlying reasons behind not ditching the current uniform in favor of the classic look. I'm sure it has something to do with money, though. I was at the game yesterday and I can't tell you how glorious it was to see the classic Broncos font and logo on the field. And I understand it was throwback day, but I think fans wearing the classic D far outnumbered the fans wearing the new logo. It just seems like Bronco fans are more prone to wearing their old gear than any other fan base in the NFL. There has to be a reason for that, right? Would anyone actually be upset if we went throwback full time?