I wouldn't read too much into that. Google Engineering has huge budgets and all kinds of random projects get paid for with no better justification than "this is good for the web, therefore it's good for us".
I worked there for years. Seeing really deep, well thought out business plans there was a rarity especially for small projects like hosting web fonts or running DNS resolvers. Heck, even for very large projects sometimes the accounting was unbelievably carefree.
Pfft.. What was I thinking? It's the original Dont-Be-Evil company, right? Of course they are giving away tons of freebies just because they are awesome. They just run a money printing press for an extra minute and those huge budgets will materialize out of thin air. Yay.
Yes, that's pretty much how it is. Don't believe it if you like, but you won't convince me: I was there in some of these meetings, I read the design docs, I watched these sorts of projects get approved. They just give this stuff away because they're swimming in money and it's a place run by geeks.
Next time you link to a .css with those wonderful free Google Fonts, ask yourself - what's in it for Google?
Then take a look at all those ajax.googleapis.com links pulling down jQuery libraries and wonder the same.