I recently read an article about "10 things we can expect from Marvel Phase 4", it was motly a wish-list of things the writer wanted from the MCU but knew he wasn't going to get out of Phase 3 after reading it I realized that as a fan-base we've kind of been spoiled rotten.
The Marvel Cinematic Universe was the first of it's kind, a cinematic meta-franchise of this magnitude had never existed before. It's frankly a miracle that it was done right. They know how to plan ahead so developments in the universe feel natural. They keep getting the right actors, they use the right tropes in the right way and whenever it starts to feel old and they know when to mix up the status quo or try new things so we never feel bored.
The MCU has given us so much good stuff that before would never have been filmed before, from the Avengers movie, to Gaurdians of the Galaxy, to Civil War, to the Daredevil and Jessica Jones Netflix shows. Rather than being complacent Marvel Studios keeps coming up with new ideas and keeps devoting time and effort into making sure that these stories turn out good. There's even more awesome stuff up on the horizon, a Luke Cage netflix series, an eventual Defenders Netflix series, a TV show based on the obscure but awesome duo of Cloak and Dagger, the Black Panther movie and the Infinity War.
It seems that we (or some of us at least) have gotten used to Marvel Studios giving us what we want and we now expect our every wish to be turned into a reality. The fact that were already speculating about Phase4 when we only just started Phase3 feels kind of ungrateful. Lets play with the toys we've got before we start whining for new ones okay?