@kingu It is a reverse case of the broken window fallacy (https://en.wikipedia.org/wiki/Parable_of_the_broken_window). The money not spent on fuel, etc. by cyclists is spent elsewhere. It is mainly a reallocation to other parts of the economy.
Parable of the broken window - Wikipedia

@MathieuP

True.

As a walker, I am not richer than people with an equivalent salary and a car.

I do have a lot more t-shirts tho. 😄