They've built over a 120 of the things so far and large amounts of American industry jobs depend on it. The Americans are not us they attempt to protect their indigenous technology industries. It is way beyond unlikely that they would ever cancel it, they will just slow procurement or buy less during the development phase which still has another two odd years to go and buy in the production phase.
Plus ok I'll bite, why is it the JSF actually '****e' can you actually define it in a way that doesn't make you look like you've thrown the toys out of the pram because we haven't bought something else please? It's like reading JSFfan's missives only in reverse.