I posit that the reason is we form a lot of habits and patterns when we are younger - like high school students or college students where most of us have more time and very little money.

Some of us reassess spending patterns over time (and even there some do it more frequently than others).

So you have this spread where a part of the population is still very frugal and some part is almost price insensitive and then everything in between.

Love to hear what other folks think.