politics

There are ways to justify this (decreasing marginal tax rates are consistent with optimal tax theory, as you get the incentive effect without the reduction in revenue on the hours that people would work anyway), but in general I'm kinda worried about tax policy being driven by memetics. Becomes a complexity nightmare.

Have you seen how the UK's universal credit works? Every payroll has to be reported to the govt in near real time so that if someone's pay is below x then they receive a top up in that period from the govt. Reporting hours worked is pretty similar to reporting £ earned in terms of complexity.