I believe I've seen evidence of exactly that happening as margins for a drug are very low if it can't be protected (via IP), and the cost to bring a drug to market is so high.
I see many problems with current IP system - but I don't see how this is avoidable in a completely commoditizable generic drug market.
If I'm making some incorrect assumptions here, I'd love to know!
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.
That's more common than most people realize (meaning something being discovered through work in an unrelated context). Look at the discovery of Penicillin as one example, there are many others.
And that wasn't what I said -- Penicillin is just one example. Look at the polymerase chain reaction, thought up during a late-night drive by a graduate student and now ubiquitous in biology and medicine. Look at the first polio vaccine, created at very low cost by someone who was so sure of his results, and so short of funds, that he used his own children as test subjects.
Examples abound. One need only look.