People in this area are more apt to have their wealth represented in where they live, not in the vehicle that they drive. Their vehicles are not their identity - the fact that they're located in Cambridge often is. Higher value cars are often a bad investment as well.

Which is often times why you see some souped-up Escalade parked outside a very low rent district - people want others to assume that they're wealthy when they're not - and those who are wealthy often times don't want to attract attention to it - especially if their priorities are more tangible and they don't give a shit about what others think.