Okay, a few points. Claiming Paizo's release of the rules as a pdf brings the "open source sensibility" is a little bit of a snub on Wizards...who released the Open Gaming License originally. I like Paizo a great deal, but they are releasing free information for free. Not that big a deal. Anyhow, Paizo (& all the slew of other OGL & d20 publishers) will keep up with 3e(ish) stuff as long as it it profitable-- heck, there are companies today publishing 1st edition material.
There are a lot of detractors of the 4e, sure-- I think they are being silly but that is neither here nor there-- & they will keep buying books. For a little while, at least. & Paizo will keep selling it to them...especially because to do otherwise would be to lay fallow for a year or so. I think looking at it as a blow to the OGL is a wrong-headed way of looking at things. Heck, increasing interest in DnD sales can only inevitably help Wizards of the Coast. That is part of why the SRD/OGL model is so interesting & successful. Buy all the Green Ronin you want! All the Mongoose books you can carry! You might want to also pick up the PHB while you are at it. CHA-CHING!!!
I think Wizards has handled DnD much better than TSR ever did. If you REALLY want to talk about Wizard's screwing Paizo, though...how about refusing the Dragon/Dungeon magazine license (almost certainly complete with a Do Not Compete clause of some kind, right?) to....publish the content online FOR PAY. What is this, 1991? Didn't this concept die out with the other dotcom dinosaurs? Pay-for-access websites? What a joke.