I think an insolvent renter is probably a smaller risk than an insolvent loanee, at least with certain assumptions. I'm not defending it, and have no background in it, but it seems possible.
But we're not talking about an insolvent renter, we're talking about a renter who's making their payments. A renter who makes payments every month at 2500 can, and regularly is, not approved for a mortgage at 2000 a month, even though--based on the payment history--the renter would not only be able to make those payments, the mortgage payment would be easier for them to make--and therefore less risky--than the rent payment.