If your business is built entirely on someone else's ecosystem there are two possible outcomes:
1. You fail or have meager success;
2. You're very successful at which point the ecosystem provider will probably judge what you do important enough to acquire you (or one of your competitors!) or compete with you and have the home advantage.
The fact that some convinced themselves that Twitter was "different" might want to refer to the Peanuts theme of Lucy and the football.