Thoughtful argument, yours...

Issue seems to be whether "sliding-scale" penalties comport with long-held "equal justice under the law" doctrine.

Not sure what part of our Constitution mandates penalties proportional to income...

What's to prevent gaming the system to reduce penalties is unclear.

What's to prevent infidels from invoking jury nullification thereby reversing your law is also unclear.

For example, your local drug dealer whose income is not a matter of public record can plead indigence just like your illegal immigrant who repeatedly commits the same offence because things are so different here.

A compromise, perhaps... three strikes... vehicle forfeiture?