If your business model isn't repeatable, then it isn't stable and won't be able to reach any sustainable size of note. It is the repeatable model that is the most stable. That's what you get in a "mature" industry.Gee, everyone has cars, does that mean that auto manufacturers are all doomed? Of course not. Their business model is repeatable. They can sustain whatever size that they grow to if they can handle the competition.
That's FNMA. FNMA has billions in profitable revenues coming in every month. It can loan out lots of new money at low interest rates and rest assured that it will continue to be successful.
And by the way, 70% homeownership isn't important to FNMA. No, it's how many homes need loans that matters. Even if America reached 100% homeownership, there would still be a demand for new home loans as people moved up, moved down, moved away, etc. In fact, it wouldn't even be a problem if no new loans were needed (an impossibility). No, what matters to FNMA is to get paid one way or another on what they have already loaned out.