Here in the States there are only 12 states I believe that have state run inspection systems and those are Yearly or bi-yearly affairs the other 38 states don't have State Inpections it's left up to the vehicle owner to keep the vehicle in good operating condition , the incentive is if involved in an accident and you have faulty equipment then you may be in hot water . This of course does not apply to Commerical Vehicles which have to pass Federal Department of Transportation checks .
Having moved from a state with very tight controls on emission limits and windshield cracks < you were limited to an inch long crack if it were into the area sweeped by the wipers> some of the States require brake drums to be removed to check for wear , to a state without Vehicle inspections where some people will drive with several cracks spanning the entire width of the windshield and tires with several wear bars showing or hardly any tread on a tire or engines that you know have not been kept in tune in a long time ........Its hard to see these kinds of faults and not be bothered by them .
And yes when my old State went from a yearly to a bi-yearly program it was the inspection station owners who complained the most , not about unsafe vehicles being on the road longer.... it was the loss of money until the system had been through its cycle.of course they got an increase in their fee from 25 to 40 dollars per vehicle.