Two for Seattle with Thomas Rawls.There's actually a pretty simple answer to this, and I'll list it here:
Le'Veon Bell
Justin Forsett
Jamaal Charles
Dion Lewis
Arian Foster
Marshawn Lynch
LeSean McCoy
Matt Forte
Chris Johnson
Mark Ingram
I'm probably missing some, but all of these players probably would have been 1,000 yard rushers if it hadn't been for missing significant time due to injury. If you assume they all make it, that gives you 17 vs the 26 WRs, which although still less is far smaller a gap. It is easier to get 1,000 yards receiving than rushing by a little, so I don't think this year is so much historically good for WRs as it is historically bad for RBs. In 2014 there were 23 players who broke 1,000 yard receiving, so it's not that significant a jump.
So what are people's thoughts about the possible rise of the old bottom teams next season? I sure we all think Raiders and Buccs are prospects.