Your point is, if I don't spend my money for a car (+ its ecosystem) then I spend my money otherwise - with a similar result?
My point is, if you don't spend your money for a car (+ its ecosystem), then you don't need so much money to make a good living.
If you travel more, buy a house etc., then you set the saving off. Then there is no effect on growth.
But if you decide to just work less (or not more, if you don't have a car yet) then this has an effect on growth.
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