The Verger has just checked up on what he thought was the case and just for the purposes of accuracy points out that Kyle is the 5th highest ranked player not yet 23. 4th was before the US Open. After which he dropped to 6th, behind Rublev and Chung, though has since retaken Chung.

Where he actually looks as a comparative prospect overall one can debate but at 23 in January he is over a year older than all the rest of the top dozen U23s apart from Kyrgios. The under 23 top ranked are actually quite a precocious bunch even relative to the U23 heading. So if Kyle plateaus any longer, very possibly even if not, I can well see him in the next year dropping behind some of the other younger players. Will he say end next year in the top 10 of U24s?  It is because to me more of the threat to his future aspirations comes from these aged younger than him than in much of the next generation up ( or to an extent his immediate peers ) that I sometimes get a bit frustrated by he himself coming out with stuff like "I am still young and developing." Of course, some real relative truth in that but err just get on with it before younger players develop quicker. His best big chances may retrospectively come earlier than some imagine.

Still, at his age he is still well placed in the big picture to push on again and move further up the overall rankings and it's being as close to the best that he personally can be that really matters, and that looks a fair bit higher than he has got to so far.

So as for this challenger / potential challenger stuff I just can't reconcile it for Kyle or such as Jared Donaldson, a now top 60 rising 20 yo player who unsurprisingly played Challengers not too long ago ( Andy was a challenger player for a time and soon became an ex-challenger player ) - a bit different from a rather older consistent challenger player, whatever constitutes a challenger player in different eyes though there does appear to be an outlier. I really don't understand the dooom laden ongoing spin to suggest otherwise but it is very Fraser.