You'd have to have huge database of what every individual bought ever. How many beers, how many condoms per month they purchase. Or at least how many times they were making purchases in sex shop, liquor store, marihuana dispensary.

Currently your payments as a customer aren't bound to your TAX is if you don't specifically opt into it and you have no reason to do that if you don't have a company.

That's increase in a intrusiveness many would strongly oppose.

You can of course compromise and base your tax progression only on the sum of large purchases that are being registered already like houses and cars and investments.

But there's still issue of charging the correct tax if you don't connect consumer with their tax id on every purchase.

I think that companies that sell directly to consumers should collect purchase tax of consumer and pay it. And the rate should be the same for all consumers. To award consumers tax credits government just could give them cash directly that will come back to the government in the form of purchase tax that consumers pay (to sellers or through payment processors that transfer it to the government).

You can still punish the rich by reducing their tax credits progressively with how much assets such as cars, real estate and investments they own.