The primary purpose of pharmaceutical companies, like all companies, is to make money. That is why they are called "companies" and not "charities." It costs over a billion dollars (that's billion with a "B") to design and develop a brand new drug from scratch. Companies can sometimes take shortcuts by developing new variations on current drugs, which they frequently do. But these so called "me too drugs" aren't the kind of novel drug discovery that we're looking for.
Vaccines in particular tend to be money losers, so no company will want to work on them without heavy government subsidies. With antibiotics, it depends. There's actually a lot of work that goes into antibiotic development. Again, however, the issue tends to be that we aren't getting new classes of antibiotics that work by novel mechanisms. Instead, we're getting new variations of the old classes that are more expensive and often not any more effective.
My PhD is in pharmaceutical design, and I've often thought that what we really need is a nonprofit pharmaceutical organization that will work on necessary but financially unprofitable projects like vaccine development. Last I checked, there was such an organization out of Cali, but it focuses on making treatments for third world nations, which, while worthwhile, doesn't do anything to help people here. I would want to focus my nonprofit on the needs of people in the US. But who's going to come do all the R&D grunt work? A
ny of you premeds up for volunteering in return for a LOR for med school??? Well, it was worth asking.