If they can't afford to fix their windshield wipers (15 EUR at most for new rubber blades), then there's no way they can afford to drive in Germany on a regular basis. 12 gallons of gasoline is around 75 EUR, or $100.
And TÃœV costs about 70 or 80 EUR - not to mention the annual car registration fees.
So, yes, if you cannot manage to fix your windshield wipers, your car should not be on the road. Take the bus.
That may be true and I'm glad that (at least some of us) in the US we strive to make driving accessible to everyone, lower their cost of living, and allowing them to take that money and feed their kids - all by allowing personal responsibility. Not wasting their time and money by fining them when they very well might not need the windshield wiper at that very moment.
Do you have any numbers to suggest the cost is worth the benefit - or that there is any benefit what-so-ever?