Cockroaches, aphids, ants are still insects we need and want. Having the distinction between good and bad insects is part of the problem. Similar problem with the distinction with good plants (grass) and bad plants (weeds). More diversity is healthier.

And if the bees continue their die-off, they'll take a majority of the mammals and insects with them, because as much as 80% of plants are pollinated by these creatures. Goodbye food chain. As if that's not enough, imagine global warming if even a 50% decline in CO2 converting plantlife were to happen.