I agree with everything you are saying. However, in certain ways it is a question of perspectives.
It would be nice if there was some organizational body that would decide, "this is a good candidate and will put it into a trial and pay for it." Then, minocycline would get its fair shot. And, I definitely believe it should. Furthermore, in US, Canada, Britain, Russia, etc. organizations of this type, typically government sponsored, exist. One may argue that they are underfunded or wasteful or inefficient in where they throw money. But, it is thir responsibility to fund a minocycline study.
I commend the drug company in stepping in and saying, "hey this looks promising, let's try it in combination with our medicine." They didn't even had to do that. One can argue that if the treatment looks good as a combination, many neuros will write minocycline prescriptions to their single episode patients, uninsured patients and the like. If the combination is deemed more effective than Copaxone alone, it will become a trial and a treatment spontaneously. I.e., look at all the people poping antibiotics without a thread of evidence. A drug company is definitely risking its dominant position with a trial like that. (I believe Copaxone is the most "effective", approved, unrestricted treatment out there today.) Minocycline is potentially Copaxone's worst nightmare.
As far as market dominance, moving out of sector, etc. arguments, I agree, it is capitalism. If there will be a treatment that is similar in effectiveness as something that just made it to market, then it may not be economically viable to pursue further development.
Nonetheless, it is a race, and even if a company has a better treatment that may not produce as much profit as something it came to market to already, it will not drop it. It has already poured a lot of money into the treatment, competitors will soon be out with better stuff, the worst it will do is slow it down a bit. But, most of the time, slowing it down is a bad move. In a race, one wants its best stuff to be the best as long as possible.
But, in any case, my point is that drug companies are not evil as many posts imply. I find it interesting catching myself arguing the beauty of capitalism and laissez-faire when I have grown up as a liberal with socialist tendencies trough my academic career.
So, to get back to my socialist side, the drug companies are picking up the slack here. I think it is in societies good to get rid of this disease. So, it is the government that should be the leader in MS research, not the private industry.
But, as long as it is the private industry doing it, we should not be bashing it.