I'd say that it could be done one step further, even: a package in, or part of, the OS, that simply installs the 100 (or ten, I don't know the usage curves) most common fonts and keeps them updated.
Isn't that what's already happening in every OS for a very long time?
The problem that web fonts are addressing is that you have the same font across all platforms, so if some OS ship with additional fonts we'd be in the same position as before: Not everyone will have this package as part of the OS and you have an inconsistent look again.
It's good because we could stop caring about FOUC and friends, but it's bad because it would give Google even more power over the web.