He was probably counting on Google, as the service provider, to backup his data for him. The way that (if you let it) Apple backs up all of your iPhone data constantly so that if you drop it in the toilet, you just get a new iPhone and everything in a few hours magically comes back the way you left it.
That's the promise of "the cloud" we keep hearing about from the marketing departments. This artist, being an artist not a tech guy, believed it.
But this is actually par for the course for Google. I moved all of my clients off of Blogger about five years ago after one of their Blogger blogs simply disappeared without a trace and no recourse. After a little digging, I turned up HUNDREDS of similar cases of people's Blogger accounts vanishing into thin air with zero help from Google. This has been going on for years, and Google is silent about it.
After all, you get what you pay for.