The important bit is this one, I think:
[WotC], in my opinion, is addicted to publishing new shiny things that were already printed before. After all, PUBLISH OR PERISH is the mantra for people in my field and for publishing companies. They HAD to make another edition of D&D to stay profitable - otherwise they were just going to run out of expansion products and ideas.
What they really need to do is completely change their business model (DDI doesn't count - that's vaporware). More and more gamers are turning to the internet and not to published hardback books for their materials. The RPG bloggers network alone provides me with enough material for more campaigns than I could ever run in my lifetime!
And that last bit is the rub: the internet changes everything. I can read tonnes of good stuff on blogs and forums, and if I want to I can cheaply or freely partake in fan-produced materials like Fight on! or Labyrinth Lord or a million and one others. (3e and 4e equivalents are also out there, if that's what floats your boat.) Who needs to buy materials the traditional way when you can download a .pdf, print it out and bind it (because it would be better to pledge your soul to satan than try to read them on an electronic format) within minutes - and when moreover there won't be the built-in redundancy which trying to keep up with new editions of the game brings?
I really wonder where WotC will go from here. I'm nowhere near churlish enough to argue that they couldn't continue to make fun versions of D&D from here until kingdom come if they had the money to. But there are only so many times you can say "Here's a new better version than the one you've been enjoying for the last few years!" before your customers start to smell rats. Role playing games are not like computer games, where graphics and processor speeds are continually evolving: there is a point at which a set of rules are good enough and require no more refinement. (Which is why nobody has successfully produced a new version of the Monopoly rules, for example.) This is especially true of rules for role playing games, whose point is not rules at all, but the concept of a shared world, which is free.