Musk could also work to make Tesla more competitive with BYD in the mainstream American car market instead of making Tesla double and then triple down on a weird niche product like the Cybertruck that will never appeal to many people. Tesla had a huge lead in EV tech that they seem to be squandering by not addressing boring stuff like build quality, giving BYD plenty of time to catch up. Their whole product line is starting to look stagnant.

Keeping BYD out won't help if all the other car makers also catch up. If BYD pulls far enough ahead they could just create a US division and make cars here like Toyota and Nissan do. Nissan is on the ropes, so maybe BYD could just buy them and make that their US brand and get all their factories and supply chains.

If Tesla kept iterating on the Model 3, released the Model E, and Musk stayed out of divisive politics that alienate customers, Tesla had a chance to own the mainstream of the US auto market for the next 50 years. I'd say that's gone now.