True, but besides insecticides and habitat destruction it is possible that the strong nocturnal lighting, which disorients insects, has contributed to this. Wherever insects are abundant, a strong white lamp at night will accumulate quickly dead insects around it.

Where I live, in Europe, when I was a child there was a great abundance of insects of many different kinds. If I did a walk around my home I could see insects from perhaps at least 10 different orders.

Nowadays, the only insects that are still abundant are the true bugs (Hemiptera) why all others have mostly disappeared (a few, like mosquitoes, may still be seen from time to time). I do not know the reason, but I assume that the true bugs might be more resistant to insecticides.