Sorry, but if you are going to use this "tell how a car handles and why by watching it" comparison, then accept that yes, it's done, done daily, and done effectively. People make very good livings doing precisely that, and doing it extremely well.
To a degree, yes, I can agree with that. A driver who's driven lots and lots of cars in his time, who knows that a novice is driving an adequately prepared vehicle, can see what's the driver's fault or not. I don't think a pro racer from the circuits could watch a novice in an unknown dune-buggy making a hash of a rally event though, because the pro racer doesn't know how the dune-buggy handles in that situation.
Comparing this to games, a person who's a seasoned pro with Halo and other FPSes can look at a novice playing Halo or similar games and see where a novice is making mistakes, but where the game deviates to a degree, they can't determine that. Consider GeoW where duck-and-cover is essential, in stark contrast to other games of that ilk. Consider an expert gamer of GeoW who wins every tournament. Could that expert look at other GeoW players and see where they're going wrong? Yep. Could that expert GeoW player look at a novice playing a different game, where duck-and-cover isn't an option, and see where they're going wrong? I think not. If I were that expert, I'd be looking at a player running out into the monsters and getting shot up and I'd be thinking 'duck and cover you doofus!' without appreciating necessarily that this particlar game doesn't
have duck-and-cover gamplay. The skills I would by looking for them to use aren't available to them. Consider an expert of fighting games that all have blocking, and then that fighter expert is asked to comment on the skills of players of a fighting game where there is no blocking. If it plays differently, his expertise doesn't give him insight. When a player is getting hammered with a 10-hit combo, the expert doesn't know whether it's that gamer's inability to block or retreat, or the rivals ability to execute an unstoppable super-move from which there's no counter.
I didn't follow this conversation enough to know what exactly the pro is supposedly loking for in the other plays, and in this case it may be right. But I dispute the idea that a pro in a field can always have insight into similar fields. It depends how much deviation from the pro's field of experience there is as to whether they can interpret what they're seeing correctly as a fault in the tools (game) or the use of them (gamer).