I think part of the bootleg culture (and passing them around) was the fact that they were unofficial and rare. That encourages people to share them and rave about the show/quality.
I just don't see that happening with official releases where they release every show of a tour. I even have friends that went to the shows that don't have any interest in the official recording of the show (which baffles me).
In the 90's the idea of having a recording of a show I actually attended seemed too good to be true.