I think medicine is still a prestigious no matter what. Even when salaries go down it will still be prestigious. It's just my opinion. However, I'm not clear what are we really discussing in this thread? Is it medicine prestige or fancy cars stigma? Do you really want to answer your own question you asked in the beginning of this thread or we are going to just talk philosophy and derail the topic like many have done in this thread already?
To answer your question: people (especially here on SDN) usually stigmatize fancy cars, because they have different background (and I'm willing to bet, majority come from families where money was and is an issue) - different priorities, they have loans, they have debts and it is generally believed here that you have to pay your loans asap by limiting yourself - including staying away from fancy cars. Most of forum members have little knowledge of how to buy a fancy car without breaking a bank and how to maintain it without overpaying tons of money to dealers. However, they have to stay on top of their financial situation and the only way for them to stay on top is to stay away from what they think is a money pit (in most cases rightfully so). Add to that peoples stereotypes (often wrong), beliefs about cars and maintenance, horror stories about debts and loans, some even hate you or your fancy car, because they have to drive economyboxes, some envy you and such and so on. Add to that students (who are majority of users on this website) who have no clear idea or very limited idea of what they want from life, how to manage their finances, even add the fact that there are so many students/residents that have peculiar mind that tells them to listen to majority of financially "smart" peers who are perceived successful and who almost made it a fashion trend to be as economical as it gets - this is no surprise that there is a stigma. Come on now. We all know it. So is there a stigma? Yes. Is it wrong? Probably yes. Is it possible to have a fancy car without investing too much? It depends, but definitely yes. Can you change this stigma? Not in foreseeable future. You'll always have a bunch of students here on SDN that will lick their snots and cry out loud about how bad having a fancy car is. Should you just accept it and keep on living happily? Yes.
P.S. You don't have to look far, just go to "Finance and Investment" section and read what kind of things folks post there. It's amazing. Students who have no idea about families, children, mortgages etc - write about retirement and talk about every detail of their already made up detailed spesific plans to rich life (or afterlife LOL). What is even more amazing to me is that majority of forum members really follow that. It's like a cult. Some of them will learn the hard way, some of them will never learn, some may even like it, but it is what it is - and you can't expect to not have stigma about fancy cars in a society like this.