Only if you abuse your statistics and choose numbers from different sources - 65% is the lowest figure for present market share and 85% is the highest for last year (http://en.wikipedia.org/wiki/Usage_share_of_web_browsers).
It's true that Microsoft are losing marketshare with IE, I'm not denying that. But I seriously doubt it's "becoming irrelevent". It's much easier to lose marketshare when you dominate a market than it is to gain it, they now have increased high-profile aggressive competition on Windows from both Apple, who are bundling Safari via iTunes Update, and Google, who are pushing Chrome on OEMs and via their search engine. Microsoft also have no version of IE for rival operating systems, particularly at a time when Apple's desktop market-share is increasing, so clearly if their desktop market share drops by 5% in a year, then that's up to 5% fewer people running IE. I actually think IE's usage figures have held up surprisingly well, considering.
This is the second day in a row I can use the same comment!
Products with >50% market-share are not irrelevant; they are VERY relevant. And as much as you might hate it, IE is not just going to die.
On the other hand, irrelevant products with disproportiate marketshare inevitably lose marketshare eventually. And the more marketshare you have, the less you can gain and the more you can lose.
Mediocre products with huge market penetration are more likely to die a horrible death because: 1) they have maxed out their growth potential, and there are fewer and fewer converts for them to target. 2) since their quality is bad, better competitors are likely to gain viral growth by only contrasting themselves to the mediocre status-quo; its name recognition will be used against it and its brand sabotaged (i.e. "Like X but doesn't suck", "a better X", "an X with ..", etc.)
@halo and @maukdaddy: the trend of marketshare of IE is downwards. It's not irrelevant now (I never said it was) but it's already becoming irrelevant: It's marketshare is going down with no obvious response from MS to stop this trend.