Well, in order to compete, they'd have to cut costs.
You can't cut costs infinitely. You still need to pay people, suppliers, and above all, people who had nothing to do with the company but hold a piece of paper saying they're entitled to profits.
It's probably the case that you cannot do that enough to compete with the Chinese if you're in the US, so they won't try.
We're in a post-"what about the long term economic outlook of our country"-era and have been since the 1970s. John Q. Public in the US and Helga Öffentlich in Germany don't care that their purchase of a Chinese EV hollows out their country's industrial base, they just care that they spent less on the EV. And why shouldn't they? The countries themselves are lead by people who do the exact same thing on a massive scale.