Patents exist to prevent the sale of innovations. The notion that I can't make a buck without a patent because someone else will undercut me may be true, but it also says that innovations will get to market without patents.
Yes, the enforcement is the manifestation of their use as a risk mitigation tool. Some innovations will get to market without patents, complex innovations requiring some threshold dollar amount will not find funding and will not (this was learned by the world of govt. science policy over the last century).
