The issue is the reverse. Shkreli used existing FDA regulations to carve out a monopoly -- from what I understand from the Wiki (
https://en.wikipedia.org/wiki/Pyrimethamine#cite_note-45), he largely leaned on current FDA bioequivalency standards to put a barrier to entry for the business that was higher than many generics would want to risk (given the low volume of the compound).
Once the virtual monopoly was obtained, he subsequently jacked up prices. In this he probably made a mistake by being way too greedy. With "ordinary" medication pricing, patients may not notice the very high prices, largely because American medical pricing is not terribly transparent. Instead, the higher costs tend to translate to higher insurance premiums and higher medical bills to the taxpayer.
Pyrimethamine is an old 1950s drug and as I understand it the synthesis is relatively easy. If the current American regulatory system wasn't so broken and we had a truly free market, Shkreli wouldn't even have a business plan with that sort of price increase, low volume notwithstanding.
The good news out of this is what Shkreli did was so egregious, the flaws in the system ended up being headline news.