You'd be surprised. There's still some people who think that when they type in a query, people at Google manually decide which results to show. For every result on the page. For every query. Hundreds of millions of times a day.
A lot of those searchers do a search for "John Smith" and then want to talk about why their school friend John Smith wasn't #1 instead of that other John Smith.
That's doesn't negate your point; I'm just saying that orders of magnitude more people want to contact Google than there are Google employees, and many of those people want to have prolonged discussions with Google. So the challenge is to find scalable ways to communicate with those people.
Adwords/Adsense customers/vendors? That is a different story. As I have mentioned several times on this topic, I have encountered shocking responses from Google regarding large ($100k+) accounts.
Google does not have that many customers & vendors.
Tens of millions of webmasters - I would suggest that only a fraction of them would need to call customer support, same with the publishers and advertisers.
Banks also have millions of customers, just when the call center is busy, they are put on hold. I think the best investment that Google cam make right now is not to sacrifice customer service in order to get on with throwing stuff on the wall and see what sticks. Instead, just hire some recent grads to deal with people's issues. How much would that cost, lets say ten grads, 100k a month each, that's 1 million, a drop in the water as far as Google is concerned. The return on this investment on the other hand would be so great as people can then continue loving Google rather than suggest that Google is being evil.