I actually thought long and hard about this issue (longer and deeper than you care to know - I study energy and how it create and shape our complex society). Of course you can save your work onto your hard drive if you want to.
I don't see this as issue at least not in the near future. When was the last time your internet went out? If it happened to you, it didn't last long.
Set up your own WebDAV presence in your own domain and sync up your git, svn, etc., revision repository to keep your local copy the most current and you don't need to worry about Google.
Domains are cheap. Administering your own Mail service, web services and development services only requires your interest and time.
I like to own my research.