How can you say this is not true then give all example that require a patent? Yes you can mine drugs that are out of patent and find new uses for it that can be patented. Do you know of one new drug that has come to market in recent years without patent protection?

Yes once a drug goes off patent and becomes generic then lots of drug companies will pick it up and start making it, but no new drugs are developed these days without patent protection.

Of course if you wanted to you could make this treatment yourself - it is not that complex.

The issue is who is going to pay for the extensive testing required to get from lab to hospital. That takes years, and lot of organizational skill, and a lot of money. If a drug has gone off-patent, all that is already done, so many companies will be glad to manufacture it. But for new treatments, somebody has to push it through clinical trials, with the (quite substantial) risk that something which looked good in the lab fails to work in larger studies, or has unforeseen side effects.

Those are all old drugs whose patents have expired. Drugs start off being patented and exclusive first.