That's an interesting argument, but it misses the fact that the US is effectively subsidizing the healthcare in the rest of the world.
Another country, no, because that would be irrational and stupid (just as it would be for the US, if the argument atht the US is actually doing that is correct.)
On the other hand, if the US is subsidizing the rest of the world, that means the US is substantially reducing the marginal benefit of expenditures in the subsidized domain by other countries, disincentivizing their own expenditures (direct or through policy which promotes drug development.) It would be irrational to expect the removal of that subsidy and the associate disincetives not to result in increased expenditures.