"Why shouldn't the sales tax on cars be the same as any other product?"
OK I'll try. Cars and houses are the only things that come to mind in this category. Yard sales might be next.
You buy a car or a house in this state, either the first time or the last time, the state is there to get its share. If the state would be satisfied with 5% on the first sale, you have a point, but each time you sell the car, the state is there to watch the title transfer. With hands out. So if the car is sold at 20,000, the tax is 1000, in three years it is sold again at 10,000, the tax is 500, and so on.
Same thing with houses, except normally the price increases. So a sales tax at %5 on the subsequent sales would really sock the buyer.
I completely and totally see what you are saying, and I do agree with you about the tax hand being out there all the time.
I was looking at it in comparison to the regressivity of a gasoline tax, which hurts the person with the lower income far more than the one with the higher income. Granted the same prinicpal applies, to a certain extent in regard to a car purchase, but not everyone buys a car every year, or a house for that matter. Therefore it is not a recurring tax on the same person.
As I said, I'm not saying I would support it, just that I would support it a lot quicker than an increasein the gasoline tax.