Having worked at a bank before (in their IT dept specifically), banks are extremely risk averse (and that extends to all aspects of the bank, from financial risks to HR risks to IT risks), and all of the loan officers I worked with were far more interested in doing their job right than being sales people.

It’s in the banks best financial interest if it’s customers get wealthier because where does that wealth go? Into the bank they already bank at. Banks need to keep a certain amount of deposits in reserve, so the more cash deposited the more money the bank can invest in financial products itself to make itself more money. If all the bank does is mint loans that customers struggle to pay back their deposits will be very low and therefore they’ll make less money.

Also sketchy loans are harder to sell as securities, as security bundles have to have balanced risk profiles both for legal compliance and for investors to be interested. Investors in mortgage backed securities (MBS) aren’t investing in MBSes for insane growth, they’re investing in a relatively safe security to park some cash in as part of their diversification