[Principled]

Under the sales tax the doctor must remit $150,000 for sales tax. Meanwhile, the drug dealer should remit $150,000 for sales tax on all the drugs he sold...

But the sales tax is collected on money spent, not earned. So the full tax burden of the doctor AND the drug dealer are collected at purchases for retail.

In the income tax scenario, tax burdens are income, payroll, and embedded. The doctor pays them all, but the drug dealer only pays a portion (the portion embedded in prices).

But again, the nrst puts 100% of one's tax burden in sales tax, which they both pay.

It should be clear that the nrst does indeed capture more of the drug dealer's taxes.

[Always Right]

But the sales tax is collected on money spent, not earned.

But the drug dealer is still collecting a gross amount and not paying tax on it. Technically you are correct, it is not the drug dealer avoiding the tax, but the drug user. But either way, there was still $150,000 of sales tax not paid. Whether it be the income tax to the drug dealer, or sales tax to the drug user, both systems has similar tax avoidance for illegal transaction.