People do care about privacy and openness, not just in the way technologists expect them to. Using Google for mail over some random company or running your own mail server is reasonable for the threats against privacy most people face. Communicating with your friends on Facebook is "open" compared to asking them to buy a specific phone, run their own servers or install software. If anything it's developers don't care about privacy and openness. They are the ones running all these companies that take advantage of open technology not (or even prevent it to) keeping up with the demands of users.
How? In this new economy, big corporations have structured themselves such that they can compete with and protect against "disruptive" startups.
Also, coming up with something more attractive takes time (trial and error), and big corporations can easily incorporate (copy) those new features in their products in the meantime.