Products grew through user growth on mobile, because those particular companies got in there first, and they were the new shiny for all of the mobile users that were discovering what they could do with their new devices.
The companies that were first and were most in tune with what works on those devices won.
On mobile it was literally about, who could provide, the best/cheapest/most viral ways to communicate that saw the biggest growth. Because that’s what worked best for the platform.
The question is, is there any unoccupied rooms left in the mobile house, and I would say probably not. Meaning the only way to succeed is if you have the funds to brute force move someone from one of those rooms and take over it for yourself. But who has the funds to unseat Twitter, Facebook, YouTube etc? nobody does.
There is one area of growth right now and that’s AI/ML. And that’s only because people aren’t quite sure what happens when you start throwing fancy algorithms and neural nets at all the data that the major platforms have and are continuously gathering.