Against Monopoly: Microsoft's Decline

I'm a big fan of the Against Monopoly site authors; here's a bold prediction from one of them:

Always in the past when software with substantial installed base has finally been supplanted the fall has not been gradual: Lotus and Wordperfect went from world-beaters to also rans in just a few years. I think Microsoft may surprise us by falling equally fast. There may not be much left in two years time.