Entirely agree with this. If I had a horse that was capable of winning a Grade 1 race, finishing 3rd in a King George (despite subsequently being found to be suffering from an infection), and then finishing 3rd in the Gold Cup, he'd be staying in training for sure. (With the proviso he was still enjoying his racing, of course.)
KS won £50,000 for finishing 3rd. He races with plenty of zest. Take Long Run out and Nicholls's old warriors would have finished 1st and 2nd. Just because one outstanding 6yo has improved past them doesn't mean they should be retired....