I agree the QB makes a huge difference. Its not too far off to say if Smitty had an elite QB his whole career he would make top 5 of all time. Rice was a great WR but having TWO back to back HOF QBs in his career did effect that sorry to say. During Rice's ENTIRE career he had the best QB in the league, it tends to make a difference.
But its like asking a what if question...it has no purpose as Fox says it is what it is.
Sometimes great WR's make the QB's better than they seem....and sometimes great QB's make the WR's better than they really are.
Rice helped Montana and Young.
Smitty helped Delhomme.
Manning1 helps Wayne.
Brees helps Colston.
It works both ways.