My dad claims that the bugs come and go in cycles and says he has seen so several times over his life. He believes that we are just in a period of low bug population and that at any time there could and will be a population explosion.
Personally I am not so optimistic. My dad moved around multiple times over his life and I would suspect different areas would naturally have varying bug densities and that is why he felt they went in cycles.
Because for myself I DO notice the decline in bugs and articles like these do scare me for the sake of humanity.