In every solution, there is always another problem elsewhere waiting to be solve. Crude oil and gas is something that as been there for ages and it's as a result of dead decay organic matters. I wouldn't say it wouldn't deplete with time but there is a scientific proof that oil is going to be here for many years that centuries are going to be gone and it will still be here but not forever, as long as it doesn't have a renewable source we should expect it to stop at one point in the future.

If you take a look at electric cars that we have today, the main motivation for them today is because of fuel issues and green house gas, we need to control green house emission because it was affecting our ozone layers and indirectly, demand for gas is going to reduce but this cars are not affordable for poor and middle class people. I want to believe it's because we are still early, with time they are going to be cheaper than gas cars and demand for fuel will reduce too.

However, only the government determines some growth. Many countries today rely on fuel even US relies on it despite been one of the countries with crude, they are the ones that can decide if fuel will become something important in our society. If they mandated fuel cars to go in extinction, trust me fuel demand will die completely. Maybe they are going to be converted to cooing gas but not going to be on cars but if the government doesn't, the market will continue to boom and the demand will continue.