Unbelievable how many people actually
prefer to not understand what they're talking about.
Here's the thing: nobody in the stats business thinks xG is the be-all and end-all. Everybody recognizes that it is a simplified stat that doesn't account for player identity, game state, shot placement, etc. Everyone understands that good teams will do better than the mean.
But the fact that the experts accept it is an imperfect stat yet still useful should be a tell, even for the most determinedly unaware members of the Caf, that it has some value. Currently there are huge efforts underway to try and incorporate things like game state measurements, passing phases and forward progression into a more advanced stat that might replace xG in due course. But even now, xG offers real insights.
To take the current Olly run, for example, while it is true that most top teams outperform xG, most only do so by around a maximum of 10%. If Utd are well above that figure, then it's worthy of note. Yes, the explanation might be that our strikers are suddenly much better than those of City and of Pool and of Spurs, or it might be that we are benefiting from a lucky streak. I love Rashford but I'm not yet sure I want to say he is better than Kane or Aguero, so maybe there's some luck involved? And if there is, then we can expect some regression to the mean. Is that a blinding insight that you couldn't make yourself by simply assuming the current run is unlikely to be maintained at this level? Not really, but as the engineer's old saying says, it's much harder to move the needle if you can't measure what you want to change.