Most of your points relate to economics and your inaccurate perception of status symbols like wearing suits and getting a car service.
JD is more intellectual than MD?
Dear god, let's hope not. I'm a lawyer and I know some dumb lawyers and some who are very smart but severely lacking in common sense. Most lawyers do work that doesn't involve things that can kill someone. Someone who wants to become a doctor has to do well in science courses, not poli sci, and then has to go to Med School, where they study science and do it for longer than law students do.
JD has much higher salary potential
So does investment banking. Does that make I-banking the most prestigious in your eyes?
JD is much more versatile - the prestige speaks for itself in many industries
So your evidence that a JD is more prestigious is that its prestige speaks for itself? Have you looked up the definition of tautology lately? Why would you say a JD is more versatile?
JD ceiling is higher - Supreme Court justices have no medical counterpart near as prestigious
Technically you don't have to be a lawyer to be a Supreme Court justice. But that's beside the point. As another poster pointed out, being a lawyer is not the same as being a judge.
The prestige of being a Supreme Court justice does not accrue to the average lawyer (or even the vase majority of above-average lawyers).
Leaving aside the judges vs. lawyers distinction, the "logic" behind this one is really flawed. Using this logic you would argue that because a jr. high school football coach could conceivably one-day make it to coaching an NFL team, then the "prestige" of being an NFL coach accrues to the jr. high school coach. That just makes no sense.
JDs in big law get car service, catered lunches, and suits - MDs have cabs/trains, cafeteria, and scrubs
Not all JDs in big law get car service. Car service is provided for some in NYC because they are working late and it's not safe for them to take the subway/train. It's possible that car service might be provided for some in DC for the same reason, but it's not a daily thing. JDs drive/bike/cab/train the same way MDs do.
When a firm brings in a catered lunch it's for some kind of event or because there's some reason why it's more cost effective to keep people in the building working over lunch rather than having them go out. In some firms the same logic applies to dinner, or in some cases dinner for a team gets billed to a client. Pharmaceutical reps bring catered lunches to doctors offices, too.
Have you noticed that most firms are business casual and prefer it that way? If I could wear scrubs to work I'd do it in a heartbeat.
JDs are sole in their ability to practice law - MDs have DO and foreign competition
Lawyers are competing with do-it-yourself legal offerings like LegalZoom.
JDs charge by hour - MDs have to deal with government dictated reimbursements
If you ask any lawyer what she hates most about practicing law, billing time will be close to the top of the list.
According to your argument here, if a painter can charge whatever he wants per hour, then that's more "prestigious" than being a doctor.
Many doctors do not have to deal with gov't (or insurance company) dictated reimbursements, but even if they do, how does that impact their "prestige"?