People do things differently.
I got into stock/share trading when I was at uni - every single time I got any cash, I bought shares with it, or put it into a term deposit. I wore the same scruffy clothes until they fell off me, didn't own a car, ate basic food, and funded myself by working my backside off academically, to make sure I had scholarships from the middle of school, through undergraduate uni & PhD, then research fellowships at Oxbridge that paid fairly little but gave me free accommodation and food. All my travel was work-related, so if I wanted to go somewhere i had to get a grant to pay for it; didn't take any holidays other than days here and there tacked onto conference/research trips. DH did much the same.
So by the time we left the studenty lifestyle, aged 34
we had basically been spending all our money on shares, and not much else. We moved to a nice small university town in the middle of nowhere, where it's cheap to live.
With (less than half of) what our shares had earnt, we managed to buy outright the kind of house that gets envious comments from our friends who are 10 years younger, left the studenty lifestyle at the end of undergrad uni, have had kids, pay for nursery, etc. We've only felt financially secure enough to feel able to try for kids since around the time we bought our house. I'm pregnant with our first child - and we should be financially secure enough to put him through school and university, and buy one or more houses in future.
Meanwhile - my sister, with exactly the same upbringing, but no motivation to do anything with money other than spend it on nice things, lives in luxury in a large, expensive city, with mountains of stuff, but is no longer allowed to have a credit card as she's racked up so much debt and been bailed out by parents so many times. Basically every time she wants anything - house deposit in posh suburb, flash car, foreign holiday, private school fees for her child - she goes running to our parents. They say "oh, the poor thing, she has such a hard life, it's so expensive to live where she does" and pay for it without blinking. That's been happening since she was a teenager.
To the outside world we probably both look like trustafarians, but the mechanisms are rather different...