I'm admittedly only speaking for a dozen agencies or so, but things are definitely better off lately than they used to be.
But I suppose if your userbase is predominantly IE6/7, then it may not be worth the effort for you.
I tried to test it in IE 6, and the browser just immediately crashes. Not like an alert box, just an instant shut down!
In the past I would have started the unpleasant task of figuring that out and fixing it up, or perhaps detecting and redirecting to a more lightweight page.
This time I said screw it - I'm done with IE 6! Call me irresponsible or lazy or whatever you want but I'm just done with IE 6 and it feels great!
By the way YouTube shows a giant warning on their page if you view it with IE 6, saying that it won't be supported in 6 months.
However if you are building websites that regular people use they still use XP and IE7... so much so that it can account for 10-30% of your website traffic.. It really pains me when HTML frameworks like Foundation 3.x drop support for IE7 and below because there is still the userbase there.
IE7/8 is not dead for most of the world yet. People who run statcounter websites are getting data from people who run their tools. I would trust if someone like Google Analytics released an average browser usage as they are more widely used. Who the F uses statcounter nowadays?
 Though you can do tricks/hacks to make it work for IE7.
Those who still have a need to support those browsers should code up and release an additional library that adds support to garlic.js so it can be used only by those that need it.
In fact, it'd be great if every library added cross browser support for old browsers as add-ons to libraries instead of making them a core part of the library.