Apple is ahead of the game much of the time, but not all of the time. They seem to have this weird, innate ability to know when its best to be first, and when its best to be... well, best. This issue (iPad resolution) is a good example.

My guess? Apple will wait for the BlackBerry Playbook, which has close to the specs Gruber mentions Apple will need to support the "iPad retina display", and see how it affects (1) the price and (2) the battery life of the Playbook. I expect screen size and resolution to be a big differentiator if we ever start seeing the plethora of Android tablets we've been promised as well, which will lead to fanboyism criticizing Apple's decision to leave the iPad's resolution at its current state until 2012.

But, if the iPad 3 does have a 'retina display', I expect it will also have battery life and system performance that will make its competitors look silly by comparison.

I think Apple, having been first into the tablet market will wait to do that tablet's resolution right.

[1]http://en.wikipedia.org/wiki/BlackBerry_PlayBook