I think you have missed the point that this thread is about antibiotics, not patent issues on products. drug companies develop drugs to, in principle at least, help medical conditions. They protect their investment in the development of these drugs through the patent system. The whole point being that the drug is effective and will be used extensively so they can sell as much as possible during the patent period.
The way antibiotics work is that their use needs to be restricted otherwise the pathogens will evolve resistance to the drugs. Hence if a new antibiotic with little or no side effects is developed, the medical profession will restrict its use, to preserve its effacity .
Therefore it is not profitable to develop antibiotics since their use will be restricted on medical grounds.
In the case of antibiotics (which is what this thread is about) the free market will not work since why would any company invest in a product that will only be use sparingly before the patent runs out?
I missed no point because as I pointed out the initial period when the drug is only available from its original manufacturer is one where the drug is used sparingly. It generally costs too much to be used in anything but the cases when it is really necessary. Drug companies are thus able to recoup their investments.
It's only when the drugs are licenced as generics that the problem of overprescribing and drug resistance becomes a problem. Thus it is a problem for the NHS not the drug companies.