I believe it's a myth that "most" IE6 are corporate environments. The diagrams about IE6 work day-weekend fluctuation wasn't that big.
I expect at least half of the active IE6 users to be users of the category "installed Win XP and doesn't care about updates or browsers". At least I know some people like this.
Digg's recent survey shows that a most of their users who are on IE 6 _[and are interested in completing a survey about what browser they use]_ are so because of work.
If someone is already in the aforementioned "installed Win XP and doesn't care about updates or browsers" category, I think it's pretty safe to assume they might be in the "doesn't want to be bother with a survey about their browser" category.
Also, the people who are not upgrading their browsers (mostly because they are not technologically savvy) are not frequenting websites like YouTube and Facebook. My grandfather doesn't know what Facebook is and is definitely still running IE6 (even though I tried to get him onto Firefox)!
do him a service and at least upgrade to IE8, it also does wonders if you just replace his 'internet' icon with a browser thats more recent, he'll never know the difference but will thank you later that he can watch videos of his grandsons on youtube.
Now if we could get Sun, IBM, and Google to all swear off IE6, maybe some IT departments would grudgingly update to IE7.