Nah - that's more of a system of control. You can definitely have a poor country where people are not slaves to mortgages. It's called building your own house. Many countries allow that.
Consider healthcare, usually older people need it more than younger people. If you have a higher proportion of older people in a population compared to younger people, you have a larger proportion of the associated costs being carried by a smaller proportion of the population, this means decreasing healthcare quality, increasing the pool of people paying in by increasing retirement age or increasing taxes. None of which are particularly good.
Mortgages are the number one cost associated with "working til you are very old".
By far in poor countries healthcare is much more affordable than in rich countries. I think one of the main outcomes of rich countries is just increased costs for everything.
Consider healthcare, usually older people need it more than younger people. If you have a higher proportion of older people in a population compared to younger people, you have a larger proportion of the associated costs being carried by a smaller proportion of the population, this means decreasing healthcare quality, increasing the pool of people paying in by increasing retirement age or increasing taxes. None of which are particularly good.