Based on this, if Google had a 10.1 inch Nexus tablet and it's specifications were comparable to the new upcoming Galaxy Note 10.1, I would be hard pressed to choose the Note over the Nexus (price tags being more or less equal).
So this is my point; Samsung not supporting their tablets beyond one (very late) major upgrade is a disadvantage compared to Nexus and iOS tablets. It should be worth it for them to upgrade the Galaxy Tab to JB to ensure new customers feel confident that their new investment in a Galaxy Note is going to be worthwhile. This is a significant investment for most people, and you tend to feel you're getting better bang for your buck with a Nexus or iDevice as it keeps fresher, longer. You can also bet that Windows RT is going to be more Nexus / iDevice like in its support cycles.
One question: I heard during the ICS release cycle last year that ICS was supposed to make this upgrade cycle much easier for the developers. The theory was that after they reskin to ICS, reskinning to JB should be much simpler. Did this ever pan out?