Do you really think

Rashford's run and proximity to the ball had no clear impact on the involved defenders, including the keeper?

I realize this isn't a classic example of 'gaining an advantage from an offside position', but...it really is. Like I said above and in my original post - you can certainly make a case for goal here based on your interpretation. But I think it's contrary to the spirit of the game.

Notice the defender to the right in the picture. Did they lay off the player who took the shot because they thought Rashford was going to strike it and they wouldn't get there? What about the keeper's positioning?

edit: here's another scenario for you. Imagine the same play, but instead of the ball being played diagonally to the middle of the field, it was done perpendicular to the goal line so only Rashford could get there.

Ball is played
Rashford gives chase, 10y+ away
Left side defender gives chase, 10y+ away
Rashford within a yard, doesn't attempt to play the ball
Defender gets close
Before defender can play the ball, AR puts his flag up for an offside offense

Now it's easy for you to say 'well that isn't an offside offense', but ask yourself this: if Rashford immediately gives up on that ball because he knows he's in an offside position, does that defender have to make that sprint to get to it? Keep in mind, 'challenging' for the ball as defined by IFAB does not need to include physical contact.