I don't know what you mean. Of course we could have, but we didn't. We didn't because building 10,000 electric cars vs 10,000 bombs is a no brainer, but building 500,000,000 cars vs the same 10,000 bombs is a different kind of problem. Intimidation and transportation scale differently. At different scales, different decisions are more likely.
- World population in 1967 was around 3.5 billion people, less than half of our current population
- The U.S. nuclear arsenal peaked at 31,000 warheads in the same year 1967
Why did we need more bombs when there were less people? Why was there a greater perceived threat when there were less people in the world to fight over resources? Why would reducing our population level by half cause a change in our behaviour when these factors seem to be independent?