Obviously it would be the other way around, discontinuing IE6 support might lead to falling. Think of random niche industries with ancient old hardware and no-one who cares about software updates.
Fair enough, but I still don't think a business that is wildly successful would fail by discontinuing IE6 support -- even in a "random niche industry" where IE6 users make up more than 2% of their customer base. In fact, I doubt any of those businesses are currently wild successes. But I guess that all depends on how you define success.
