There were far, far worse things out there than Subversion. VSS, ClearCase, an obscure commercial one written in Java whose name escapes me now..
Subversion was basically a better CVS. My recollection is that plenty of people were more than happy to switch to CVS or Subversion (even on Windows) if it meant they could escape from something as legitimately awful as VSS. Whereas the switch from Subversion to Git or Mercurial had more to do with the additional powers of the newer tools than the problems of the older ones.
