The IL-96 is about as old technology as the 767, last I checked.
As a US taxpayer, I want the most bang for the buck:
*The USAF wants a KC-135 sized refueler.
*Tankers get 3-400 hours a year utilization - a tenth that of airliners.
*Price is driven by competition.
-------
The 757 is about the same size as the KC-135. There are plenty of used 757 out of the 1,000 built that are parked and available for a few $Million each.
There are dozens of MRO, Maintenance, Repair and Overhaul organizations around the world who are capable of tanker retrofit, meaning the price will fall to the level of the dumbest competitor.
Used A310s are available. That would be an alternate tanker that is already proven.
Converting airliner to tanker is not rocket science, and the planes would be available quickly and at a fraction of cost of new.
We don't need a tanker to last 10 years, let alone 20 or 50, unless we need to do aerial refueling of UAVs.
--------
What is the biggest obstacle to converted tankers? Lower cost means less money for lobbyists.
GB