Your narrative actually supports the opposite position. Why would big pharma companies buy "little, fleet-of-foot companies" if they could simply wait for those companies to develop a drug, copy the formula, then bury those companies using their huge advertising budgets? The winning strategy in a world without patents in an industry with high R&D requirements is to never develop anything new, but spend all your money on advertising and building an efficient outsourced manufacturing operation.

Just look at the PC industry, where the technology is all open and commoditized. Acer, Lenovo, Asus, etc, own the market, nobody makes any real money, and nobody tries to innovate because new designs are easily copied and margins are razor-thin.