So what?! They are operating within the constraints of the market. Before the vulture capitalists swooped in prices were very reasonable for 30 years, the previous owners chose not to exploit their monopoly, then these two increased their efficiency.
they didn't increase efficiency at all, they just increase the amount they were able to squeeze out of the IP. thats not an efficiency vs inefficiency, its n vs n+1.
It's not that they started producing more units, it's that some folks (the ones using the drugs) were taking advantage of a market inefficiency (the insufficiently low price) which when corrected, meant greater returns for Shkreli et al.
Just as when a "retail" day trader hits on a system that enables them to make a large amount of money, they're taking advantage of an inefficiency, and, in a way, helping to correct it.
It's not pretty, but being ugly doesn't make it inaccurate.