> I'm afraid that making a drug un-patentable would make it /less/ likely that it goes to market

This is definitely a possible outcome.

http://biz.yahoo.com/p/5qpmu.html

generics manufacturers make ~ 6% margin, which is basically "what most businesses make". "Drug manufacturers - Major" make 20% margin. Keep in mind also that big pharma spends about as much on advertising as they do on R&D.