It seems to me that the 707 and C130 airframes provided similar multi-role benefits to the US military (eg. tanker, special transport, AWACS, JSTARS, TACAMO; transport, tanker, gunship). It seems strange to me that the same arguments don't stand with today's equipment.
It would make sense: the Russians use the IL-76 airframe for many different roles: Strategic/Tactical airlifter (Il-76), Air to Air refueller (Il-78), Awacs (A-50), a waterbomber (Il-78P). They also have an ELINT version, A zero gravity trainer, A SAR version that can air drop a seagoing rescue boats, and several others. The aircraft even has four hard points under the wings, just in case....
The C-17 could propably do all of the above, the only point being, can they do it as cheaply and as effeciently as other aircraft. The brand new Il-76s that were sold to India a few years ago only cost about 35 million dollars and Russia, which owned its own oil companies, did not care if the beast burned 9 tons of fuel an hour......