Here the only reason why the company is able to charge a large amount of money is because they've gone through the whole process of tests and clinical trials to get the drug available for consumption. That's an entirely different kettle of fish than the expert knowledge $9999 you mention above.

The gist of the article isn't about expert knowledge, it's that a fairly simple chemical compound (the name itself gives the simplicity away - dimethyl fumerate is too short to be anything horrendously complicated) is jacked up in price, and that someone suffering from the disease could presumably get the drug made themselves for much less than $50,000 per annum.