So they are the exact same difficulty? Or not?
I guess I'll reply to myself.
Of course they're not the same. It's easier to score a league goal in the last 2 seasons for Liverpool than it is for Villa, we're a vastly superior team, with vastly superior players, coached by a vastly superior manager (sorry Emery, sorry not sorry Stevie).
But of course the numbers you post don't take that in to consideration do they? Because they can't. Every goal is created equal in their eyes, there's no weighting applied at all.
But for the sake of arguement you believe that yeah, it's just as easy/difficult for Watkins to score his goals as it is for Darwin to score his. There's no difference between turning out for villa in this period of time to turning out for Liverpool.
Where do you draw the line in that case? Is it just as easy to score a goal for West Ham? Is it flat in terms of difficulty to score for wolves? Is it the case for any player who hits 0.49 goals per 90 has done so under the exact same conditions making their respective performances in doing so the exact same level of impressive?
Watkins' gp90 are more impressive than Darwin's because they've come under significantly more difficult circumstances. Simply saying they've the same 0.49 goals per 90 therefore it's the same level of performance is omitting that.