I’d ask that coworker, “so you would be okay with paying $10 per gallon of gas, while the Prius that barely uses gas next to you pays only $3 per gallon? You us

I’d ask that coworker, “so you would be okay with paying $10 per gallon of gas, while the Prius that barely uses gas next to you pays only $3 per gallon? You use more gas, which means it is in your budget to afford, right?” (Or pick another alternative that is applicable.) Inverting the argument almost always exposes cracks, because they will immediately switch to why it’s not the same.