I concur with this. I drove an RV for a period - possibly the least aerodynamic vehicle around. It was a losing battle to keep it remotely clean of bugs. Now driving in the same areas in a normal vehicle, it is a practically non existent problem.
I think it does. I don't remember the bugs being nearly so bad back in the 1960s and 1970s as they are now where I live, but I never have to clean off the windshield of my car. When I was a youth we would fight for the privilege of squeegeeing the windshield at every gas fill-up. Now, it's hard to go out without drawing a cloud and even the dog wants to stay inside in the summer.
I suspect automobile aerodynamics play a bigger role in the windscreen index reduction than ecological destruction does.
I'm sure aerodynamics play a part, but insect population decline is a very real issue. You (and your dog) may think you have a "bug problem" where you live, but the wider picture is grim.
https://www.nhm.ac.uk/discover/news/2019/february/the-world-... https://www.pnas.org/doi/10.1073/pnas.2023989118
It's possible that modern aerodynamic cars are better at avoiding bugs than old cars, although I don't know if this explains the whole difference.