There are many multi billion dollar companies that do pharmaceutical research outside the US, their revenue is not exclusively from the US, suggesting there would be no healthcare without the US, is like suggesting there would be no cars without the US
Merck isn't a US company, it is a German company. There is a US company with the same name that originates from a seizure of US assets of the German company with the same name.
Also known as the Merck that actually invents new drugs and rakes in almost three times the revenue of the German counterpart. I wonder if the fact that it's a US company has something to do with that. Hmm.