Think about how artificial a 50-year mortgage is.
It's 5-7% for some amount that's at least 6-figures where the term is unknown due to possible repayment at any time.
Would you take the other side of the trade? Would anyone? The term is too unpredictable, the amount too much and the interest rate not nearly enough for all the risk.
Yet these happen all day long because they're not loans created from savings, but loans created from nothing.
50-year mortgages are an abomination. But so are all other mortgages that come from nothing.