Sheesh youre persistent. Of course there is a symbiotic relationship but an easy litmus test to see who benefitted more is how they performed apart from each other.
Rice/Taylor. We dont really know. John always had Jerry and Jerry was almost done by the time he got to Oakland. (Timmy was already good btw)
Irvin/Harper. This one is obvious Irvin is in the hall and Harper was out of the league within two years of leaving Dallas.
Smith/Mac Eddie was a decent receiver for the Niners before he came to the Broncos. and became a pro bowler when he played alongside rod and Terrell and Shannon and Elway. Rod continued to be a pro bowler after Eddie got hurt.
Dt and anyone else. A again the thing that you keep missing is that I'm not detracting from the other player. What I am saying is the other player benefits more from the relationship than the number one receiver does because inherently the number one receiver will always see more shade from a safety over the top and will always be playing opposite the other teams best cornerback.
Did Demaryius benefit from playing with Wes Welker of course. Did he benefit from playing with Decker of course. Did he benefit from playing with Sanders of course. But who saw the most benefit from the relationship? It is not a 50/50 deal. he is carrying the brunt of said relationship. He is carrying the heaviest weight. He is the guy again getting more double coverage and seeing more number one cornerbacks across the line of scrimmage.
The last two analogies are somewhat of outliers because they were essentially truly 50/50 relationships where both players were Hall of Famers and both players were good apart from each other. Chris Carter benefited obviously from Randy Moss but he was already a Friend Hall of Famer. Randy Moss may have benefited a little bit more not necessarily on the field but off because of Chris's mentorship. Bruce and Holt are both fantastic players in their own right and both deserve to be in the Hall of Fame