I think the gesture is nice but personally I don't think its worth the effort, simply because the advantage of each IVB-E SKU is a negligible upgrade compared to the corresponding SB-E SKU. The only sensible upgrade path I can currently think of is from 4 core SB-E to 6 core IVB-E, and even then choosing a 6core SB-E is not much of a downgrade. People new to the 2011 would appreciate PCIE 3.0 among other things they could have brought in. I haven't done my homework on the 4U constant full load and whether the power benefit is worth it over SB-E though, so my point might not be valid for that.
Well the effort in releasing Ivy Bridge-E is really only up to Intel. Also note that after upgrading their FAB it makes sense to make use of it given the cost of the upgrade and a smaller process makes sense from that perspective for any processors they deem worthy.
The extreme series is a low yield high margin part one would think which tapers off with the middle and entry level processors. Intel already likely expect lower sales numbers accordingly just as they did for Sandy Bridge-E.
When you think back to Bloomfield and the LGA1366 platform one can point to Gulftown and say there were significant upgrade options before the platform was superseded. While true most Gulftown processors were well out of the price range of people looking to upgrade at ~$1000 or so. Even today a Core i7 975 or 970 will cost in the ~$700+ range. So I think its noteworthy that Intel is providing high-end options and processor refreshes for LGA2011 in a more palatable price range (~300 to ~1000 rather then ~$700 to ~$1000).
People arguing against such an upgrade option are also coming close to making the point that perhaps processors should be soldered to the motherboard. After all, no one wants an upgrade option anyway,....right!?!
Also as you said not everyone is upgrading so the performance delta between Sandy Bridge-E and Ivy Bridge-E isn't necessarily an issue (for some) anymore then the performance delta between Sandy Bridge and Ivy Bridge or Haswell is an issue for those on an older platform. There are also power savings to consider / calculate.
If a platform isn't for you (your use case) then I see nothing wrong with acknowledging that fact but its quite another thing to suggest it shouldn't even exist simply because its wasn't designed for your specific use case.