In theory but the difficulty in practice is that if you were to invest in local manufacturing you'd have to be sure that someone else won't be given a waver via lobbying / corruption and will then be able to completely undercut you. The current US administration lacks the credibility to give such assurances. Given existing models are exempt you're better of just delaying new models while you wait for a new admin.

I don't think it follows that a Democrat administration would reverse this.

I'm not sure the democrats could give such assurances either. If domestic manufacturing is 2x as expensive that's a lot of money that could be spent on campaign donations and still break even.

Then it needs careful consideration and compromise. Ramming through a change is just another signal that they can't get anyone to agree to it.

“Long and hard” is not something the US does anymore. You would be insane to invest here based on the assumption that the current tariffs and regulations will survive any period of time. Even Trump changes his mind every week, probably based on whoever pays most.