The whole regulatory system is not designed with antibiotics in mind. One of the biggest problems is if you bring a new antibiotic to market the doctors will be

The whole regulatory system is not designed with antibiotics in mind. One of the biggest problems is if you bring a new antibiotic to market the doctors will be reluctant to use it as they will want to keep it for those emergency cases when all the other antibiotics don't work. As a pharmaceutical company you have put an enormous amount of money into developing a new drug and them nobody buys it. Rather than go down this path most of the pharma companies have just decided to produce the the things we really need like erectile dysfunction drugs.