How to synthesize quartus vqm or vo files

.vo files, for some reason I've never looked into, are not supposed to be synthesizable. VQM files can be, but only by Quartus. I've never heard of anyone writing libraries for other synthesis tools. Why would you want to do that? For starters, I'm guessing there are some legal issues(Quartus synthesis is free but I bet there's something stating it's results must target Altera devices). But it seems like you're adding another step that will be much more painful then targeting RTL, and open you up to technicaly issues(did I map this right, how do I functionally verify it, etc.). And of course the results will be big and slow, since the second synthesis tool won't have any high-level code to work with, just low-level gates.