Not necessarily, I've noticed the same thing as the OP driving the same car, a small hatchback I bought 4 and a half years ago. One or two years after I had bought it I could still see lots of dead bugs on my windshield whenever I was driving to my parents, who live in the countryside, but during the last year or so the windshield has started to be more and more clean after each such trip. The same thing has been independently confirmed/noticed by my dad, as he likes to wash my car whenever I get to them, he told me that there used to be more dead bugs on the car.
What's scary for me is the speed with which things have changed for the worse as I remember a comment I made on this website about 2 years ago saying that I could still see lots of dead insects on my car after a highway trip, in response to a couple of HN-ers who lived in Western Europe saying they didn't (I live in Eastern Europe).
Same route, same drive 20 years on, and the grille is virtually clean.
Anecdata, I know, but it absolutely is something I've noticed, and the aero didn't change.
Smoother airflow around the windshield means fewer bugs smashing into it and more glancing hits that don't leave a mess.
Traditional hard edged cars like Jeep Wrangler seem to get a lot of bugs on the windshield (based on brief Googling), so while there may be fewer insects I'd wager to guess aerodynamics is large factor.