Yet you focus on UDR's which on their own aren't a very good indicator of stable performance. Which contradicts your assertion that the All Stars seem to peak for the big races. So for example a horse could run out of the placings in the lead up races to a Group race then win. It would have a poor UDR but nabs the big pile of bacon.
But you knew that and you knew on the big day the All Stars would be primed and ready. The reality is it is very hard to keep a horse at the elite level of performance for a long time. No point winding your horse up for an Open race worth $20k when the target is the $500k race two starts away.
Anyone who has been involved in training a horse knows that.
I've seen it first had recently where in the two weeks prior to the big dance no stone was unturned in ensuring the horse was ready. Full vet checks, bloods tested, diet supplements and more.