By the time when, Google will be our overlords. Running the world with no one to be able to resist their ironclad rule. Because they know you, they know where your most loved live, what you need most to live, what your habits are, what medications you need.
Doesn't that sound bit too pessimistic? Of course it does. You already trusted Google, why trust another company and risk your data?
What if, from the 10 companies you trust your data with, 2 of the go rogue and use your data against you? OR what if they get hacked, and lose everything? That's what I fear more than giving too much data to Google. I'd rather trust one super reliable guy (Google), than trusting 5 (Self hosting) maybe trust-able, 3 shady guys, and 2 unreliable guys. But that's just me, I make sure all my accounts have 2 step auth.