your proposal, and it’s current incarnation is a major part of the problem - we have far too many people taking out of the system without putting anything into it. they simply have no interest in conserving money since none if it is theirs. if they pay something, then they have an interest in cost containment.
There is no way to make someone pay what they don’t have, and poverty level means that is what it takes for a single human to survive. There is nothing left of it to tax, take 10% and you either give it back in welfare or they die.
It would also encourage everyone to work at least enough to make that tax free 12K. They might learn to become productive and get a real job.
A perfect description for the occupation known as "politician"!