You are right that we COULD do many of these things. But we won't. We live in a society of people who deny there is even a problem. Anyone who knows it's either powerless or looking to profit.

Humans work on crisis management. We ignore a problem until it bites us in the face. Then we band together and defeat it. Unfortunately, when a problem exists that can't be corrected by the time it bites us, no banding together will stop it.