I drive long distances through Europe every now and then since 2009-ish. That's only 12 years and much of my drive is through farmland and forests, no lights other than the cars for at least 1000km in aggregate. In 2009 the windshield and lights would need a solid scrub every couple hundred km. Now I don't bother cleaning when refuelling.
In according to the more usual explanations I've been working if lights along the road might be part of the problem.