The reality is that there's no real "catch-all" age for WRs and QBs, because it depends on how good they are. Elite WRs obviously stay good longer than average WRs. Ditto that for QBs.
With that said, it's extremely rare for any WR to still be fantasy relevant at age 36.
True or not, much has been made on how RB's have a significant dropoff once they reach the age of 30. Just wondering is there is similar proof/evidence (historically speaking) of what the dropoff age is for QB's and WR's
There is similar evidence for WRs and QBs--that is, none at all. The 30 year old thing is complete hokum for RBs, and while you could come up with a similar number for WRs and QBs, it would also be complete hokum.
Hokum? Not in the slightest. Let's set a baseline for fantasy relevance. I'm going to set it at 100 points. Why 100? Because only once this entire decade has a WR ranked in the top 36 (i.e. "starting fantasy WR") while scoring fewer than 100 points. Deion Branch managed to finish as WR36 in 2003... with 99 points.52 times in NFL history has a 32 year old WR finished with 100+ points
40 times in NFL history has a 33 year old WR finished with 100+ points
28 times in NFL history has a 34 year old WR finished with 100+ points
14 times in NFL history has a 35 year old WR finished with 100+ points
8 times in NFL history has a 36 year old WR finished with 100+ points
2 times in NFL history has a 37 year old WR finished with 100+ points (Jerry Rice and Charlie Joyner)
2 times in NFL history has a 38 year old WR finished with 100+ points (Rice and Joyner)
1 time in NFL history has a 39 year old WR finished with 100+ points (Rice)
1 time in NFL history has a 40 year old WR finished with 100+ points (Rice)
No WR has ever scored 100+ points at age 41 or older.
Jerry Rice and Charlie Joyner are the only WRs in NFL history to still be playing at 39. Jerry Rice is the only WR in NFL history to still be playing at 40.
Now, anyone that says that a WR is guaranteed to be irrelevant the day after his 36th birthday is full of it. With that said, it's the furthest thing from hokum to look at the evidence and say that WRs
TEND TO really fall off at a certain age.