Most of Titanic was filled in Mexico, where they could get a seaside drydock to build an actual, floodable, almost life size set. (Side note - about a dozen of the tech crew came up after they were done shooting and did tandems at Air Adventures while I worked there. They wouldn't tell us what they were working on, other than it involved a boat.)
Now consider what it would have cost to rent out half a mile of ocean coastline - with power and road access - anywhere in the US for six months.
Absolutely. There will still be films they can make. Just not as many, and many of them will be more expensive. The result will be a smaller US film industry.