No sense in supporting a browser that will become irrelevant in 6 months.
Charts like this are helpful because they give us a sense for the current, global browser-usage climate and trends. However, global statistics alone should never be used to determine which browsers your site should support, as a cross-section of your niche of users may vary widely from this data.
Google's snarky messages would invite people to download Chrome, while Apple's would try to convince people to download Safari. Combined with the fact that people still using IE6 of their own volition would be most likely to blame Microsoft for "breaking the Internet" and switch to a different browser, it would not be in Microsoft's best interests to coordinate something like this.
In addition, television advertising made sense for switching off analog television, since the people most likely to be affected would be watching. Even if even one of the three companies you mentioned put up money for television advertising, it would be a waste of resources. Targeted banner ads would be better.
Actually, I'm surprised Google hasn't tried anything like this yet. Given how many ie6'ers use Google everyday, I bet a nonintrusive, hide-able message on search results pages encouraging them to 'upgrade' to Chrome would go a long way towards increasing their marketshare.
It doesn't seem to appear using any other browser.
So they're getting pretty close to doing that; perhaps less obtrusively than you suggest, but the intent is there.
It could be, but I don't think it is. Every other browser supplier has the right to -- and does -- put up web pages suggesting people use their browser; they also have the right to put up other content on their websites, which may or may not drive traffic to them. I note that the Microsoft home page has an ad for IE8 on it, and this isn't anti-competitive either.
Jusdt because Google is successful, doesn't mean they're anti-competitive. Now if they fiddled with their web site so other people's browsers didn't work properly, or fiddled with their browser so other people's websites were poorly rendered, that would be uncompetitive.
http://developer.yahoo.com/yui/articles/gbs/
But IE6 under Windows XP continues to cling on, and it isn't in their forecast for the next quarter:
http://yuiblog.com/blog/2009/07/02/gbs-update-20090702/
Which means Yahoo, at least, expects IE6 to still be relevant in 6 months.
On the other hand, startups can afford to show a "crappy looking" version of the site since its more or less expected. + the % of IE6 users is much smaller for startups, since startups typically have early adopter users.
and not a browser like another, one that will require radical changes to your site code in order to barely work.