I struggle to reconcile this with the number of cash buyers, though. Higher rates aren't going to affect their ability to pay.
Why? aren't the rates locked in for the duration of the mortgage (25/30 years)? The only way I can think of this going wrong is doing your budgeting when the rate is 2.5% and then not taking the rising rates into account, but presumably the bank will cut them off first.
With a purchase mortgage the bank is involved in the transaction in multiple ways, for the bank's protection. Appraisal, inspection, etc. You're saying there is some magic wand to be waved that makes the bank not care about its exposure anymore?