I think the OP is failing to realize a few things,
First, you are totally ignoring the development costs of releasing new tech extremely quickly, especially when you consider that the current iteration is having no issues selling, and won't for the foreseeable future.
Let's just say the development cost for a version of the iPad is ~50mil (totally made up number, no clue what they cost to design, could be 10mil or 500mil)
Now let's say that apple is meeting or exceeding their sales expectations (don't even try and act like they won't)
Why would apple bother to release a 3rd gen tablet and waste all the development costs on a device prematurely?
Apple also likes to wait between generations of other companies devices so that it looks like they are more advanced than they are.
Apple will probably wait until a few months after the 3rd gen (if you consider xoom 2nd gen) Honeycomb tablets come out to release their new even moar better tablet. This gives them time to better match their specs to the competition and increases the chances of us seeing a retina display.
What I could see Apple release in like 6months, is a LTE iPad 2.
Anyways, the other really large issue in your theory is the current situation in Japan, while the effects likely won't be THAT dramatic for Apple, it will cause delays in both manufacture, and adjustments in design for unreleased devices which will also cause delays.
The bigger effect will be the delays on other companies, which will reduce the demand for Apple to update quickly.
Do you honestly think Apple will have a hard time moving iPad 2s come Christmas time?
The original iPad was outselling the Xoom despite the difference in specs, Apple sells an experience, not just a product, and that isn't going to change.
There are also a few flaws in your reasoning, you talk about the competition heating up, but from where I'm standing, at least for now, it looks like the iPad is slaughtering everything else, and I don't think that's going to change just because someone slaps some more ram or a faster processor in a non iPad tablet.
As for your statements regarding the holiday season, while I'm sure tablets will do decent sales during the holidays, that's not really what apple is aiming for, the iPad's price is a bit beyond your average gift price, and it isn't really a necessity type buy, what apple is targeting is something far more heinous...
Tax return checks. People LOVE to spend their tax returns of unessential things, (that's how I got my iPad this year)
Apple also doesn't want to overlap their releases too close to each other, the last thing apple wants to do is cannibalize their own sales because customers ran out of money on the last product 2 months ago.
Long story short, all of your theory is based on the idea that Apple is facing any sort of real risk of losing the tablet market, or that anything coming in the next 3-6 months will really be anything more than a similarly spec'd device that is running a less refined OS and or will somehow find the hipness that Apple currently enjoys. Alot of what's to come also depend on what apple does with iOS 5.
At the end of the day I just can't see why Apple would NEED to release a new iPad early. I'm not saying they couldn't, Apple could release a tablet in 2-3 months that would outspec the 2, but why would they? Anyone who was going to buy an iPad for Christmas isn't going to be waiting for March anyway.
One last thing you are ignoring are the risks in upsetting customers be releasing earlier than they expected, and the dangers in meeting supply during holiday season. Production for the iPad 2 is just ramping up, and clearly is not currently meeting demand. So Apple is currently tooling around to get iPad 2 production up to snuff, they also are probably beginning to work on backend production for the iPhone 5. It will probably be 3-6 months before production of the iPad can truly meet demand, especially with Japan.
Releasing early would mean retooling your entire production line and during holiday season the demand would be SUBSTANTIALLY greater, and customers are far more inclined to become extremely upset when they can't get ahold of their precious device in time for Christmas.
It also would raise costs as Apple would have to source new parts, a big part of the reason the iPad is at the quality it is for the price it is, is the volume and length of term which Apple buys the parts for it's products. Apple is able to buy in extremely large volume BECAUSE the product cycle is long. They can secure long term contracts for specific parts because they aren't constantly changing them.
Anyways. Time for sleep.
IMO there will be no TRUE iPad 3 in 2011 (4g is possible though)