Adjusted for inflation the price of oil isn't even the highest it's been this decade, let alone historically.
The price tripled from 2003-2008 as well.
>The war did not had to start at all
We probably won't know for twenty years if that's true or not. It's not as Iran's been some peaceful country for the last twenty years, they actively have sponsored terrorist organizations with the purpose of destabilizing the region. The country also sits on a wealth of natural resources but was solely researching nuclear power for peaceful purposes.
Really the big lesson for the next superpower is to simply act earlier. If you don't care about winning and just being a thorn in everyone's side, ballistic missiles are a great investment, and it should have been taken more seriously when Iran started stockpiling thousands of them.