I'd read that Brighton's xG meant that they were getting into the right positions, but just couldn't convert. So, by that logic, if they had a better finisher (who could also get into the same positions), they'd be a lot higher.
I'd like to think someone then did the same analysis for all the other clubs. As you say, give any club a better finisher, and oddly they'd do better. But I just read it about Brighton in isolation. So, I think it's trotted out a bit lazily about Brighton, now. Perhaps the gap was larger for Brighton than the others.
Anyway, can't stop to chat. I'm finishing my "If Shane Long could finish, Saints would have won the Champions League" article for the Athletic.