I don't think it's possible to teach anyone to be careful and fastidious with money..... You either are, or you aren't. It's a gene or personality trait that's hardwired and pretty unbendable. If anything, expecting them to learn "the hard way" probably just makes them worse - it drives them underground and they hide their antics from you.
I believe you are wrong there, I'm of an age where both my parents were brought up in severe austerity (the Depression) and my dad in particular would never, ever buy anything on what was known as hire purchase (or as my dad referred to it,
the never-never), he would ALWAYS save up to buy something. That was his reaction to having had to wear hand-me-down shoes from his elder
sister when he was a boy, and living in a rat-infested tenement slum. It never left him, and despite being generous in many ways he was incredibly careful with money, to the nth degree.
This attitude was drummed into me, as I got older I became more pragmatic, nevertheless 99% of the time I would only buy something when I already had the money, or if I got a loan I would make sure 100% I'd be able to pay it off (only once in my life, to buy a brand new car).
Whether this would work these days is another matter, expectations are much higher, but then again, so is reliance on social assistance, there is overall less self-reliance than there used to be. Perhaps this is a step-up for society and enables it to grow better, but there are indeed many feckless people around these days, justifying their forays into crime with the 'need' to buy £300 trainers and the like.
I think this is part of the nature/nurture balance which is applicable in all areas of growing up, but if the nurture is very strong then it tips the balance IMO.