I'm not sure about other business model they've, but afaik huge license fee is required for setting up a server providing flash multimedia contents. The catch is that Adobe decides how much the license fee is, determined by your business and scale.

I know because I once helped a company setting up one. Later they drewback because Adobe was going to charge them more than they can bear.

Of course, there are opensource alternatives for setting up flash media servers, but still the clients are not opensourced, and controlled by Adobe. Slight change in client version might mean shutting down of service for many opensource flash media servers.