In view of that, it's only natural that big segments of software beyond the OS like word processors are also stagnant. We don't actually need a diverse marketplace of competing word processing ideas anymore... the problem is fundamentally solved as far as the public is concerned. It's not as exciting for software developers, but it's totally natural for it to happen.
Now if you do want page layout, I think the people who like to do that use something different — not Word. So I don't think they've really cornered any market, unless the market is people who want to use Word.