Digital was a complete new technology with a built in ready made market which rarely happens. And digital didn't come in ready to fly. They had, and still have a ways to go technologically as new advances are made which fits their business model perfectly.
Millions converted and the ease of use made millions more jump on the wagon. And you're right, that it will hit a saturation point just like analog did. When that happens, you change your business model but certainly not now.
So I'm missing what your point is.