Firstly, you really shouldn't label people that don't worry about the upgrade path when buying as sealed box fans, and inferring that they aren't hardware enthusiasts. It may not be your intention, but it is coming across to me as a bit arrogant and elitest.
We build the box to do what it needs, selecting the components just as carefully as anyone else building there own rig.
when it needs upgrading we will upgrade it with what is available. My current rig has had several upgrades, GPU, additional RAM, PSU, HD, Monitor and even keyboards, so it has definitely not been a sealed box.
You don't have to spend a fortune on hardware to be a hardware enthusiast, replacing something every 1-2 months or even more frequently. With 9 rigs I can't afford too. I am also a steam locomotive enthusiast, and I have NO intention whatsoever of buying one of those. My dad owned one and that was close enough for me.
Nows thats over and back to the thread.
Intel now has two processor streams for the desktop.
1156 and 1366. 1156 is for mainstream, and 1366 is for extreme market. We have already seen that Intel have started to take the 1366 upwards, in the way that left the 920 alone but removed the higher end 9x0 in favour of faster ones. Intel need to get daylight between the two platforms for there strategy to work.
The difference between an i7 860 and i7 920 in gaming/corporate is negligible and Intel will need to remove the overlap, otherwise they will cannabilize sales of the 1366 systems into large corporate accounts, which is where they really make there money. Large corporates are sealed box environments so the fact that can't upgrade isn't an issue. People that would have bought the cheaper 1366 will therefore buy a high end 1156 or find the extra for the 1366 system anyway. By moving the 1366 upwards then can maintain a better margin on the product.
As such Intel has no incentive to keep a cheap 1366 cpu around, as they will need to ramp speed on the 1156 to combat AMD and ensure remain ahead, in the mainstream sector.
Some of the i7 920 owners will be able to afford to upgrade to the i9 series, however I don't see it as a large percentage of i7 1366 owners being able to afford to do so, as Intel have no incentive to keep a cheap 1366 around. That is what the 1156 platform is for.
Intel will keep the i7 920 around to help the partners shift the last of there x58 boards out the door, but after that they have no need to keep such a chip around.
Gigabyte appear to have cancelled the A revision of there x58 boards and already apparently withdrawn the GA-EX58-UD4P. Overclockers also seem to be reducing the number of x58 board available as well, which is another good indicator, that the 1366 processors aren't going to continue selling as well, and main focus will be on 1156 processors. Other sites also seem to be reducing 1366 and x58 as well.
If the retailers aren't seeing a big future for 1366 then is likely to be that they aren't seeing the demand for them. Biggest cause is that not very likely to be affordable.