Surely, Google has way too much power, but as the old adage goes: don't put all your eggs into one basket :)
You might not want to be tied to Microsoft but Google is not the only option.
Edit: Overlooked the comment about Apps. Microsoft offers apps for mobile, but not Linux. Although even on Windows I use the browser to access the services which will work on Linux.
What's needed is a syndication of data, and inter-operable apps. Like how xmpp worked. But of course, all vendors don't like this, because it turns themselves into a commodity.