



If the company fails to keep some bodies frozen, then confidence in it will drastically drop (especially for issues like this) and new patients will really stop paying for it. The influx of new patients is one factor that might help pay for it.
If the maintenance of existing frozen patients depends on an increasing influx of new patients, then what you have there is a pyramid scheme. If, on the other hand, you can expect to benefit from economics of scale, then the number of new patients needed over time to keep the business alive may stabilize, in which case it's not a pyramid.
Something else to consider: Once the revival technology works, you're not going to revive all the frozen people at once. You're only going to revive those whose underlying medical problem can be fixed. And the frozen heads pretty much have to wait for upload tech.
Once you start reviving, you now have a small population of extremely grateful people. But, by the above assumption, you're going to have fewer people getting frozen because more underlying medical problems can just be fixed without freezing and waiting.
If the maintenance of existing frozen patients depends on an increasing influx of new patients
It's not that they need an increasing number of patients to keep going. It's just that without new patients, business will stagnate. They'd do anything to keep growing.
Also, once they know they can revive people, it will be clear that these things failing will mean people dying. At this point, people will do anything to keep them from failing.