Gleemax remains the dumbest name I have heard for anything in the last few years. Its collapse does not bode well for the company. I suspect 4e is not too far behind.
You're right about the collapse not being a good thing for Wizards, but I'm not sure what you mean by "suspect" when you say that 4e is not too far behind. Suspect as in "guess", "hope", "predict"? I don't dismiss the idea, but I would say that it's not one of those things that can be reliably determined by the facts at present.
Look at the Dark Heresy (WH 40K) role playing game. That thing sold out on pre-orders, and then was cancelled a couple days after its launch. It was then taken up by another company (though I'd say its future is in doubt, insofar as the initial concept called for a 3-game series exploring Inquisitors, Rogue Traders and finally Marines). Anyway, selling out on pre-order is about as successful as you can expect a launch to be, and yet it got ditched. And many products that don't do nearly as well get retained, for better or worse.
I'd say it ultimately depends on the strategy hatched at Hasbro corporate. Probably the people making the big decisions have never even seen a role playing game being played, are not sure what it is and if it is really all that different from this Yuggie-O thing, and figure that if it's a game and it doesn't involve golf clubs it's probably for 12-year olds. So there's no sense applying very much logic to analysis of the situation. These guys will be looking at quarterly sales reports and that's about it, unless I'm wrong and they're some sort of business-gaming savants who actually know something about their products.
4E's lifespan will probably be dictated not by its impressive launch, but by the way the current plan unfolds. Will people keep gobbling up the supplemental products at a comparable rate to the core books? After all, a big launch was to be expected... everybody was curious (even me, though my curiosity finally got beaten out of me by stupid Amazon). But does it have legs? Gleemax going down doesn't speak directly to that, but it is a dent in the business plan. If DDI fails, then I think that 4E will have to do surprisingly well to keep from getting cancelled/sold/shrinkified.
If 4E does get hosed by Hasbro corporate, I think it will be an effect of what I continue to think is its main flaw: it's too radical. It pleases people who didn't like D&D in the first place, but how much will they buy? Whereas it angers or drives away many people who have been boosters of the brand for years or even decades. You cannot treat your legacy customers with contempt and not expect some ill effect. Note that I'm not saying that everybody who is an old timer hates 4E... there are some people who are big D&D geeks from way back who like 4E, even those who like it better than what has come before. But it's a very divisive game, and it effectively bifurcated their existing customer base. That's not a winning strategy most of the time, and if 4E fails it will have been because of that.