There's a lot more to it than just income.  Living costs, future expected earnings, how much you have saved, whether you have kids education to pay for, etc.  I would not expect $250k / year income to be enough to afford a $250k car in most instances IMO.

Say you are 30 years old, making $250k / year.  Did you just start making $250k because you graduated from medical school and finished residency?  Chances are you have $0 to your name and probably even in debt due to school.  Maybe you live in San Francisco where a decent apartment is $4k a month.  Then $250k car is ridiculous.  You won't have enough left over to save for retirement.  And if you have to choose between taking your girlfriend to a nice dinner once a week or owning a McLaren, then you cannot afford the car.

On the other hand, maybe you live in an area with very low housing costs, no kids, and have already saved in the 7 figures for retirement.  Buying a $250k car still doesn't make financial sense, but easier to justify in this case.

Personally I would not buy a $250k car without making at least 7 figures a year (or have already saved enough for retirement), but it depends on a lot of circumstances.