TrainerRoad claim that improving your FTP will improve performance on every type of cycling event from track sprints to gran fondo
I think it is broadly right because riders who are fast in long distance time trials are almost invariably also fast over shorter distances. However, there is some scope to change the shape of the curve a bit by focusing on a particular segment of it and neglecting another.
I’m sure they will not have focused on FTP only, and therefore shorter efforts.
My point was that you can focus soley on improving your ftp and indeed succeed in that task. But when it comes to longer durations over many hours , if you’ve neglected that side , you may end up slower.
Yes, but I think we're saying slightly different things.
That would be an example of someone's curve having taken a particular shape by deliberately avoiding training for longer events. So yes, I would agree that, if you make a special effort not to be any good at events of more than an hour, you could well achieve that. So someone who trains for 10s and does lots of VO2 max and intervals, but never rides for over two hours wouldn't be much good over a 24. And lots of people do that and don't bother with long events (which is why I phrased it the way round that I did - while pretty much everyone who is fast over long events is also fast over short ones, not everyone who is fast over short events is fast over long ones, as most don't do them).
But is such a person not fast over long events because they don't have the fitness, or is it because they don't have the conditioning? I suspect it is the latter because it is usually relatively easy for someone who is fast over short distances to become fast over long ones just by doing a few longer rides.