Very interesting point, Ethio Boy. It is quite conceivable that had he won in 1996 and/or 2000, he would have felt satisfied enough at 1500m to move up and focus on the 5000m, in which case who knows how much he could have achieved at that distance (in my own estimation I would say sub-12:40 was certainly in the cards). As it was, after 1996 and 2000 he felt he had to continue with the 1500 to vindicate himself.
A similar case has been made about Coe. Some would say (and I agree with them) that Coe probably stuck with the 800m much longer than he should have, seeking that elusive championship gold. As a result, he may very well have been sacrificing what he could have accomplished at the longer distances had he focused on 1500m+.
Of course, all of this is just hypothetical "what if?" But it is still an intriguing exercise and is certainly exciting to consider the array "what might have beens." I for one think that had he won the 1500m in 2000, el G would have gone on to become one of the greatest, if not the greatest, 5000m runners of all time.