Realistically no serious Google user is going to try and replace all of Gmail, Calendar, Contacts, Drive, Reader (now defunct), Chrome, Search, Youtube, Android, (and whatever other Google tools that I'm not recalling) at the same time.
I like having stuff like contacts and calendar synced between my desktop and smartphone. Google does that really, really well.
I've moved my RSS feeds over to Tiny Tiny RSS, and like that model - I control it.
I want to eliminate Chrome next because (I thought) it would be easy to change over to Firefox or Opera, but that is proving somewhat more difficult than I expected.
Can I move my contact lists away from Google and still have them sync between desktop and phone? That may be the next project.
Or perhaps I'll look at how I can move my calendar out of Google. I don't know.
The point is that once you're used to that lovely Google integration of many essential functions, and the overall ease of spreading that over multiple devices, it can really hard to extricate yourself.
Probably be Google's design of course - they certainly have learned much from Apple's model.
And would I like to get away from Android? You bet. Even flashed Cyanogenmod a couple of times on my last phone. Sadly the smartphone equivalent to Mint Linux isn't quite here yet.
But when it does arrive I'll be ready.
(Note: the problem with add-ons like XMarks is that it becomes just one more thing that needs to be watched over or maintained. The other nice thing about staying with Google, or Apple, or even a major Linux distro is that stuff tends to just work, and do so reliably without a lot of fiddling.)