"Remind me again why I should trust a company with centralized control of my data"
You should trust them because the penalty clauses in the contract make it really bad for them if you suffer any kind of outage and so they'll make every conceivable effort to deliver. Just like any other kind of service or product that you buy in from outside, in other words. Businesses have been doing this for years and I really don't see what the fuss is about.
Obviously it would be bonkers if you didn't have any such clauses in the contract ...