why is this even something that the gov needs to worry about directly? why don't they just force airports / airlines to have to pay for these guys like in UK, Canada, or Germany?
The FAA has a $5.20 tax per flight segment per passenger and a 7.5% ticket tax. The budget set by congress limits how much the FAA can spend on air traffic control, and the surplus (there is a surplus) goes into the AATF: https://en.wikipedia.org/wiki/Airport_and_Airway_Trust_Fund
This is a direct cost of American austerity.