While it's true that the exposure of top European firms can be often 50%+ of total revenue from U.S, that:

- Doesn't make them non viable without the American market, just less rich.

- Doesn't reflect the 5 to 10 times higher price Americans pay for the same drugs.

You can have a healthy industries with plenty of billions to be around and have decently priced drugs.

What you get in the US is uber profitable industries and people scrapping around.