Isn't it? An average car gets ~25mpg and travels ~14,000 miles per year. That then adds up to a total of $480. Hard to estimate the average value of a car on the road, the average used car sales price is probably a good proxy (misses some value for first-owner cars, overvalues last-owner cars) which gives $28000 (2021 was likely abnormally high and this'll actually drop some, but still). So then, you're talking 1.7% when parent was asking for 2.5%. I wouldn't call that "not sizable".

If you're driving in CA with an average car and average number of miles, gas taxes will be another $400 per year (and it's $0.68 per gallon not $0.5)

On top of that if you bought an average priced car, the 7.5% sales tax would be another one time $4000 charge

Is $4000 + $600 per year on average not sizable?

$7000 for five years of unlimited access to californian roadways and vehicle infrastructure? Ignoring the damage done to the environment and community health, the state is on the hook for $70b in maintenance in the same amount of time. So no, not really

If you ever priced out how much is costs to store a vehicle on private property, the states taxes and fees are a good deal.

exactly. The taxpayer shouldn't be subsidizing good deals on parking

30 million vehicles registered in a recent year, about half of which are “automobiles” and commercial vehicles which are heavier get taxed a lot more

So yeah i think it’s an adequate tax