It's a serious question. I know Google is more ubiquitous than ever, and despite some solid efforts by Bing, it's still, by far, the number one search engine in the world - and it's still growing.
However, I'm not asking whether you're using Google; I'm asking whether you actually open the Google homepage, and search from there. Because I don't. Until a while ago, occasionally - perhaps out of habit - I'd open it and search from there, but lately I never do it. Searching directly from Firefox or Chrome is one step less, and I'm not going to do something the hard way if I don't have a good reason.
I don't think it's just me. You don't really need to ever type Google.com into your browser; regardless of what device or software you're using, you can almost invariably skip that step. And yes, many users are probably still opening Google.com for various reasons, but when there's an easier route available, it's only logical that more and more people start taking it.
What tipped me off is the recent onslaught of Google logos. A couple of years ago I'd get a bunch of tips from friends about it: hey, have you seen Google? It's really cool. Lately, I get less and less of those; since Google's doodles don't appear in the search results [*edit: they don't show up in search results on Google versions for individual countries], people obviously don't see them [*edit: as much] any more.
Which also makes me wonder about Google's frequent logo changes and their plans for the homepage. Today, I have a reason to open Google.com: there's a bar code instead of the Google logo there. Maybe Google has realized that people simply aren't that interested in visiting Google.com, and they're spicing it up with different logos every couple of days.
Logo changes, I'm afraid, won't be enough to keep user interest. Once, it was really cool to see a company as big as Google pay someone a tribute by changing their logo (most major companies would never, ever, change their logo, even as a joke). Now, it's happening too often. Today, Google's logo is completely incomprehensible (unless you can read bar code), but the stunt isn't as impressive as it once was.
What'll Google do with the homepage when logo switching stops being news? Even if people completely stop opening Google.com directly, Google won't lose much traffic, as everyone is still conducting Google searches and opening the result pages. But having people actually visiting your site - which, in Google's case, is notoriously devoid of all advertisements, and any superfluous elements - has certain benefits; brand recognition and better connection with your users come to mind. It's tough to predict; after all, Google's changes to the homepage were so minute that it's almost identical to the original version presented in 1998. For Google, "redesign" means moving something a couple of pixels to the side; anything more than that would be a revolution.