I would think a nontrivial part of the insect thing was related to the lights in use. They would attract bugs. Newer light sources just seem to be less interesting to bugs. I think it's related to the amount of infrared output by the lamps, but I honestly have no idea. I'm no bug expert.
I'm certain it also has something to do with how many bugs have been killed on a massive scale, either from pollution or habitat destruction or something. Again, I'm no expert on any of this, so IDK.