Wasn't all that being done for Live Search too though? And that market share was way below Bing's and dropping. It's something more than just those 3 items.

Let's take a couple:
"IE is derived from Mosaic, the original Web browser, open source with a license similar to Apache's." The implication is that Microsoft took Mosaic for free and then subverted it. While all browsers date their lineage back to Mosaic, Microsoft didn't base IE on open source code. Instead it licensed Spyglass which wasn't open.

"Vista's customer-hostile emphasis on digital rights management, often handicapping its own features in suspicion that the user might have illicit content, caused its downfall. IT managers won't stand for that, and thus Microsoft has a lot of code to trash and rewrite before it can make an acceptable server platform." Does Perens know anything about the server market about which he speaks? Microsoft has a server OS called Windows Server 2008 and it's selling quite well. It isn't the same as Vista and doesn't have the same perceived problems. Microsoft has a huge part of this market. Perens tries to use slight of hand by conflating Vista and Server 2008 but they are not the same OS.

He may or may not be right on his reasoning about why Microsoft is joining the Apache foundation, but the rest of the article is based on so many false premises that I'm skpetical about the objectiveness of his analysis.