So when Trump proposes subsidizing waiters and waitresses by making their tips tax free (for example

Except that's not a "subsidy". It's their money in the first place.
You're arguing that basically the government "subsidizes" its citizens by only taking some of what we earn. It's the other way around: we pay the government to provide certain services and everyone is taxed to some degree or other to fund those things...the money isn't the government's to begin with.

The subsidy was there when it was priced at $40K. The subsidy was there when it was priced at $48.5K. So how did the subsidy raise the prices?

Ford is taking a bath on its EVs and probably thought a lower introductory price would spur more demand. The broader question with EVs in general is, "What is the total addressable market (TAM)?"

Is the TAM limited to fans of electric vehicles or early adopters of new tech? Then the ceiling is 10-20% of the automotive ecosystem.
If the TAM could be considered to be most of the automotive industry, then the ceiling is much higher.

The point there is that Ford and others have to rationalize their product offerings with whatever the realistic TAM would be.