The question has never been "Can you trust cloud services?"

It's "Can you trust them more than the alternatives?"

Yes, you can almost certainly keep your private data more secure in a system you build and monitor yourself(1). Until an NSA or GCHQ-level entity takes interest in you, and uses a 0-day exploit on your system or just physically walks in with a warrant and steals your physical media. How is that functionally different from "If the NSA / GCHQ takes interest in you, they can have the cloud service provider hand your data over?" And that's before you add the overhead of maintaining, securing, and physically protecting your own systems.

(1) Note that even this step is a huge hurdle for most people; "You cannot trust cloud services" basically tells those people "Don't use the Internet."

There is a massive, massive difference between automatically slurping all data coming in and out of a cloud provider, and going after somebody with a targeted exploit or physically seizing machines.

I'd rather make them go through the trouble of getting my data physically then just typing

  grab * -ss 834-29-1293

or whatever they do.

Is 834-29-1293 your actual SSN? :\

834 was never used as an area number:

http://www.socialsecurity.gov/employer/ssns/HGJune2411_final...

The difference is the same that enable a police officer to walk the street, but require a warrant before entering a home.

Even NSA do not like to invade peoples homes. Its a health risk for agents, its costly, it competes with other agencies, and its bad for PR. The legal steps required are also much smaller when asking a cloud service to hands over information.