The TOS is short, but the arguably more important Privacy Policy for Google products is still huge: http://www.google.com/policies/privacy/
It's actually longer than the "existing" policy, but covers a lot more of Google's services under one umbrella.
In any case, a TOS is basically governed by ordinary contract law, which allows for a much more generalized, principles-based document.
Privacy policies are increasingly governed by regulatory requirements, and those requirements are increasingly demanding a fair bit of specificity, so you're seeing an inevitable and likely permanent state of affairs.
The length of the new privacy policy still seems to counter the assertion that this is something people will find easy to read.
What about relative to all the documents being replaced?