Ultimately, Final Demand got outstayed by Kitzbuhel and even though Kitzbuhel’s pedigree suggests that 3m would be beyond him, horses often outrun their pedigree (see Gaelic Warrior who has a middle distance flat pedigree) and had the Brown Advisory been an extra furlong Kitzbuhel would have likely put more distance into Final Demand by the line.
Final Demand reminds me a little bit of Allaho, in that 3m might just be the upper limit of his stamina, if you watch the way he travelled through the Brown Advisory he obviously has a very high cruising speed and taking advantage of that weapon and just blasting off in front over 2½m of say the Ryanair (like Allaho did) maybe the better way to go rather than trying to hold onto him to get the trip in a Gold Cup.