I remember the first time someone pointed out this lack of bug splatter to me and I was a bit scared about humanity's fate, but then someone else pointed out that our cars are a LOT more aerodynamic now. Not sure which side to land on here.
Overview: https://www.nhm.ac.uk/discover/news/2022/may/uks-flying-inse...
Study PDF: https://cdn.buglife.org.uk/2022/05/Bugs-Matter-2021-National...
How much is hard to say. Aerodynamics is just hard but basically as the car moves through air it pushes air out of the way and this air also pushes other air out of the way and thus elements next to each other will effect each other.
And though I can’t find the link again, it has been claimed that a more aerodynamic vehicle should get more bug splatter. I don’t remember why, attack angle maybe?