Debt to income(usually salary or pension) ratio is what counts. Credit underwriters look at the debt-to-income (DTI) ratio, not your debt to assets. For non-investment properties, Fannie/Freddie doesn't care much about your reserves. Zero to two months of reserves is enough.
When you get a mortgage, it is actually a loan against your income earning ability secured by collateral. Credit card is the same except for the collateral part. The collateral is there in case you default (not for payments) since you can't pull cash out of the walls easily. If you pay 80% down with zero income, you will not get the mortgage. Automatic denial for conventional financing.
To survive an Amex FR unscathed, they pull your IRS income taxes, not your asset statements from the brokerage or bank. Income is what you need to survive the FR, not assets. Income is what pays the bills for normal people. People who MS with lots of assets in Serve accounts waiting to pay CC are not normal people.