Don't you think that Arabian armies retreating from oil fields (I assume they would be defeated rather quickly) would try to destroy oil fields? After destruction of oil fields prices would be horrible increased. Automotive industry would be forced to seek alternative fuels (maybe electrical engines), Soviet Union would became richer sue to its oil trade which would led to no Gorbachev as economy is not in bad shape. Or contrary, Chernenko or other old First Secretary could still choose him as young politician and his reforms would work.