Maybe this helps answer the question of 'where did the bugs go', because windshields aren't as full of them today compared to 20-30 years ago.
There's a Wikipedia entry for that: https://en.wikipedia.org/wiki/Windshield_phenomenon
wow this would be a neat twist if true - we all defaulted to the negative explanation of having killed them all where a much more positive explanation might be that we're no longer luring them to their deaths at the leading edge of automobiles?
I guess it is most likely some combination of the above, but if there's any evidence it would be a neat reframing
My hypothesis is better wind tunnel testing for modern cars so that the bugs go over instead of splatting.
I think they just all collectively got tired of hearing my dad's punny about "it doesn't have the guts to do that again" any time a bug squashed on the windscreen.
The answer to that is pesticides. There's still plenty of insects ready to smash into your windshield in many parts of the world.