But honestly, as you have highlighted, these announcements should be insulting to users' intelligence.
"Dear Users: Please allow us to store copies of all your sensitive data, including every email ever sent or received, in perpetuity. In return, to the extent the law permits us to do so, we'll let you know (_ex post facto_) when some other third party is having a look at it."
The solution to the problem if indeed there is a problem here is not going to come from Google.
The problem _is_ Google.
The only parties who need a copy of an email are the sender and the recipient. If you really care about privacy, security, whatever, then "store and forward" and "POP" via some third party (Google, etc.) is not the proper way to implement email.
Hypothesis: Google does not charge for Gmail because, quite simply, no one would pay.