Youre forgetting that most people even living at their parents saving 100% of their income couldnt realistically buy a house cash in 3 years, if at all.
It's also unrealistic that we should have to bunk with our parents and spend 0$ on anything ever to afford the cheapest house. That's definitely not how our parents lived. I have a buddy living rent free at my house atm, and I dont get angry when he spends 100$ at the bar instead of on his next apartment, people need to live a bit too and 100$ is inconsequential, at least it should be.
By squandering I didn't mean never spend a dime on yourself. But be realistic about your entertainment needs. Do you need a $5000 pc? Or would the $1500 one meet and exceed all your needs? Stuff like that. Should you go out and spend $100 a night at the bar when someone is being really generous and letting you live for free? Or maybe be mindful and have a bar budget?