I totally agree with this.
It's a sport with way too many variables that you often cannot control or make sense of. For the most part they've (Yanks mainly) tried to lift and shift data models used in those sports and applied them to football.
I wouldn't mind betting that's why we've had so many stinking signings in the last 10 years. They're probably there scratching their head wondering why Player X didn't work out, but if you understood the sport properly instead of looking at a spreadsheet it would have been bloody obvious.