How can we have a middle class without oil?

How can we have a middle class without oil? Someone told me that in countries with high gas prices, there's no middle class. There's just the rich and the poor. I don't know if I agree with that, so here's my real question: When Earth runs out of oil, how can we continue to have a middle class?How can we have a middle class without oil?
Someone was wrong. Europe has very high gas prices because they tax gas and less income inequality than the US. Most oil producing countries have low gas prices and high income inequality. If the earth runs out of oil before we find a substitute we will only have poor people.How can we have a middle class without oil?
What middle class? The middle class have been on the endangered list since the 1960s and I believe in the early third millennium they actually went extinct?!
Then you'll create electric trolleybuses, and your middle-class will take the bus - and this will refresh the atmosphere
we find another fuel source