I don't know that the details about the drug market are particularly important here. This is just another tragedy of the commons effect. Drug resistant infect

I don't know that the details about the drug market are particularly important here. This is just another tragedy of the commons effect. Drug resistant infections are a "problem" (a very severe one to those suffering), but they're an economically insignificant problem. So no one is willing to pay enough for new/unresisted drugs to make it worth their development. There are plenty of straightforward ways to get these drugs to patients. They just aren't ever acceptable to the people regulating research funding and the drug market.