Not really, they still make money from someone if they've had a mortgage for a minimum period. They're still making the interest every month until it is paid back, even early. If someone pays back money early then it means they can lend out more (assuming leverage limits are being enforced). And, depending on the initial conditions of the mortgage, they may even get more money because of early repayment fees.

In the UK there are mortgages available for those doing consulting work (i.e. not on a regular salary). They generally have an interest rate about 2% higher than mortgages available for those with salaries.