Sorry to continue with the football analogies. Why didn't England pick Gazza for France 98? Why didn't Beckham get selected for London 2012? We all wanted to see them - and KP - play. The common denominator is age. And performances (also mismanagement of talents, but that falls in the NGB structural changes and the way we ID talent in this country). As soon as KP wasn't impacting on the results of games, they had an excuse to let him go. It may well be that all were not selected for rocking the boat, being a sideshow, being bigger than the building, but there are also very valid reasons for not selecting them, in the NGBs minds, that they can use to justify their decisions. KP's knee isn't going to get any better as he gets older, he can't retrace what he said in his book.
Obviously with a 5-0 loss it'd be churlish to suggest that KP affected the results - but - and this is a huge but - did you not notice that he was always the wicket the Aussies wanted. That wasn't a McGrath style behead the oppo style wicket a la Cook, it was a genuine fear that Pietersen could utterly humiliate them in a session.
He could be over the hill, but we're talking about 11 months on from the best innings by an English player in India ever, 20 on from him treating Dale Steyn like a club bowler. I'd say that, if that version of Pietersen had deteriorated by 20% he'd still be a light year ahead of guys like Taylor, Vince, Robson and, much as I like the lad, Balance...