There's plenty of drugs that are made by multiple companies. It might not make sense for a very specific drug which sees low use, but I think it's viable to produce a drug that might be beneficial to virtually anyone even if you don't have exclusivity.
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.
