The type of risk that you propose to take has a fundamental issue for startups. As a startup, you can't do anything to make a platform itself ultra-popular. Say

The type of risk that you propose to take has a fundamental issue for startups. As a startup, you can't do anything to make a platform itself ultra-popular. Say, you develop a new hip location-based service for Palm Web OS, but Palm Web OS never passes a few million users. You can do nada about it. But what is worse, during that time, you don't learn much about your own service, because your biggest problem is to get any users for it. When you then decide to port it to more successful platforms, you still don't know what works, what gets people excited about your service etc. In a contrast, on an ultra-popular platform, if your service goes unrecognized, you can do something about it and you can learn from your efforts. You try out different marketing techniques, maybe they don't work, but all the time you are learning and getting feedback of your effors.