Firefox did most of the early damage to IE all it's own. Taking IE down from an insane 90+% marketshare position and steadily eating up 30% marketshare by the time Chrome even really showed up. And it didn't even have to stealth install itself with every adobe flash update to do it.
There were "tiny upticks" but, going slowly and steadily, in August 2008 Firefox had gained about 30-33% and IE was down to about 60%. And then (September 2008) Chrome happened.
They were obviously wrong.
Then Chrome happened. If Google doesn't change some fundamental things, they'll be the next one to fall for similar reasons.
I'd be less concerned for them if I didn't see signs of decline with Android as well. It is a key component for them to control.