You are nuts if you think that "nobody" will pay a huge price for drugs if they can get it cheap overseas. Currently, most cannot legally get drugs overseas, and they need drugs like Humira and Cadillac insurance pays for it but with an annual cap and lifetime cap. Humira costs an average of $4,500 per dose. A "monopoly" is if you hold the Patent to that drug and currently a lot of these expensive drugs are not LEGALLY obtainable overseas and with drugs like Humira, special handling is required, it has to be refrigerated, etc. (it's a biotech).
If that company holds the PATENT to that drug, no other company has that drug and there is no generic form until the patent expires. If it is a life-saving drug, the company cannot unreasonably withhold the drug. But they hold patents. See also evergreening.
https://en.m.wikipedia.org/wiki/Evergreening