You're confusing what people can do with what they actually do. I've known people who make close to the median income and support 4 children, own a home, and still had enough savings to buy them all cars and pay for their college tuition. They have some amount of retirement savings as well, though I don't know how much. I've also known people who make nearly 6 figures and just spend all of their money. A more expensive apartment than they need, a more expensive car than they need, eating at restaurants all the time, buying a bunch of what are essentially toys for adults, etc.
Although this is in the midwest, the cost of living is much lower here. It's quite possible that you just can't do this on your typical "middle class" income in other places.
> I've known people who make close to the median income and support 4 children, own a home, and still had enough savings to buy them all cars and pay for their college tuition.
You just said, in effect, they had enough savings to spend them later to meet basic expenditures needed in raising children in their income level, which isn't really a sign of ability to accumulate excess capital after maintenance.
Ownership costs in Vancouver and Toronto are sitting well north of 75% of the median income for individuals in those areas.
This isn't a made up issue caused by young kids eschewing spendthrift habits and buying all them dang newfangled iPhones rather than investing in equity building houses. It is an issue with the ratio of home prices to local median incomes.
Although this is in the midwest, the cost of living is much lower here. It's quite possible that you just can't do this on your typical "middle class" income in other places.