If we have the tech to entirely wipe out mosquitoes and cockroaches, why shouldn't we? Are they really that irreplaceable?

I know the textbook answer is always "food chain" and "ecosystem balance." But honestly, what would actually happen if mosquitoes and cockroaches vanished tomorrow?

Would the birds and frogs really starve to death, or would they just adapt and eat other bugs? Are there any scientists who argue that the human lives saved and disease eradicated would vastly outweigh the ecological cost?