The problem is that just having the income and savings doesn’t necessarily guarantee that you’ll be as good about paying back a loan as someone of your same income and savings.
That’s supposed to be where the credit score helps, but the current system is so shady that it basically just reads as the ol’ boys club system but asking pretty please to pretend there’s a formula and method being used.
I think there are plenty of failsafe mechanisms. But most importantly, if you fail to pay your mortgage, the bank has the right to take possession of your house. Those forces the bank to do it’s due diligence with regards to the value of the house. Also, if a bank has been too lenient with its mortgages, it can get into serious trouble - the government here enforces pretty strict rules to prevent people from getting in over their heads.