“Mill Reef, Nijinsky, Shergar or Dancing Brave (horse one can see once in a lifetime.”
I saw two of those in my lifetime, and plenty of people would have seen all four. So they weren’t really “once in a lifetime” horses, were they?
On the subject of Troy himself, he was obviously a top class horse but i wouldn’t put him amongst the greats, although it must be conceded that different people will have their own definition of that vastly overused term.