I'm not sure why it was a good season for them. Like you say, traffic, lighting, pesticide sprays on farms, all really the same despite COVID. Reduced air traffic I don't think would have an affect? Even after I sprayed my vineyard with insecticide to deal with japanese beetles they were fine, and continued to prosper in and around there.
It may just be that we've had an unusually hot dry year, I assume where you have as well. Maybe that's advantageous for them somehow?
I wonder if this is cyclical behavior. We had a year like that last year down in NJ. This year it was back to maybe only a week. I live in the west part of the state surrounded by parkland. Rainfall was the only thing that was dramatically different this year. Last year was extremely wet spring and early summer (when they appeared) followed by an extremely dry end of summer into fall. This year we've had average rain in almost every month. The rain evidence isn't anecdotal, I have a state rainfall gauge a couple miles down the road from me with records going back at least a few decades.
One of my favorite memories of cycling through the midwest in the early 90's was watching the redwing blackbird population slowly recover.
Most individual people won’t feel the change that’s happened over their lifetime unless they’re wondering why it doesn’t snow any more or how they ever managed without air conditioning; it shows up in higher costs for national-scale-multi-year weather damage or crop and fishing productivity.
And of course, this is a global rather than local effect, so some places have more change than others. My first trip to the USA was the 2014/15 winter when there was simultaneously record cold on the Atlantic coast and record warm on the Pacific coast.
Yet, the vast majority of scientists who study ecosystems disagree: https://ipbes.net/sites/default/files/ipbes_7_10_add.1_en_1....
By 2015, the bugs has drastically diminished enough for me to remark upon it before coming across any studies. The confounding factor here though is that the county I was in had a lot of development in it over that time. My routes stayed mostly the same (meaning both ‘where I drove’ and ‘how many buildings were along them’) but I can’t discount the expansion of the surrounding sprawl as a big factor.
Even after I moved to a neighboring more-rural county though, with a longer commute to the same workplace, I did not really see an increase.
Even accounting for this, there is sufficient evidence for a significant drop in insect populations. While it's hard to have exact numbers, the estimations in decline of population range from 70% to 90% since the 1980.
[1] https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.5236
[1] https://en.m.wikipedia.org/wiki/Automobile_drag_coefficient
We also had the sub-Brood XIII cicadas launch out in the western suburbs which was insane. They came early and they came out in huge numbers.
And at any rate, specialization only works if the problems stay relatively stable, or temporary. If we aren't stopped/don't stop ourselves we will keep inventing new insults every ten years and nothing can adapt to anywhere near that rate of change.
You're also forgetting the Carboniferous period. It took 50 million years for anything to puzzle out how to benefit from surplus lignin. In 50 million years are we going to be around? In 50 million years is anyone going to remember that Alpha Centauri is a system humans used to live in (before we used it up)?
I understand fireflies are sensitive to light pollution. I can't imagine Chicago's any different from other major cities. COVID has people staying home a lot more but that has nothing to do with street lighting. I wonder what's going on.
I do think that living organisms are extraordinarily adaptable if the changes are gradual and bounded. Most of us have this idea that an ecosystem is this delicate and fragile thing, but nature actually has a lot of robustness and redundancies built-in (which are inefficient but increase chances of group survival).