A woefully inadequate subsidy, which phases out entirely too soon.

Are vehicles subsidies the best way to drive progress on battery density and cost?

They need to be if you are going to use them to reward wealthy Tesla investors and vehicle buyers.

Yes. Increase them, and tax SUVs and pickup trucks to fund the subsidy. Regressive taxes are bad, but you aren’t entitled to drive a gas guzzler, merely access to wheels (hybrids, subcompacts, sedans, etc). Internalize the externalities.