You're right, you didn't say RBs getting hurt was the new norm, I mis-read that, my apologies.
1-Since you asked that I don't "Don't put words in my mouth," would you mind returning the favor? I never said a player underperforming "at all" makes you a bust or disappointment. There's a hell of a lot of difference between being the 1st RB picked, and finishing as the 2nd RB then there is is being the 3rd WR picked and finishing as the 15th WR (AGAIN, I'm talking non-PPR). DT was a bust/disappointment (whichever term you prefer); finishing as WR 15 when you were the 3rd WR picked is disappointing.
2-You can assume that, and you can very well be right. I admitted that I didn't factor Dalton's early injury (in the Pitt) game into my earlier post.
3-This section is long; I provided the names to avoid ambiguity; if you prefer to skip it, look to the red font at the end.
Using real draft info for 12-team leagues conducted after 8/25/15 from
MFL.com:
So based on REAL draft ADP:
bust/disappointment rate at RB has gone from 50% in 2013 to 50% in 2014 to 70% this year.
bust/disappointment rate at WR has gone from 25% in 2013 to 43% in 2014 to 56% this year.
bust disappointment rate at QB(top-12 ADP) has gone from 25% in 2013 to 33% in 2014 to 50% this year.
So, yeah, there are more busts/disappointments from top RB picks, but there are a significant amount at WR & TE, too. The bust rate has been increasing for all 3 positions over the last 3 years as well.
Take what you will from this data, but I'm not sure it supports your premise that QBs get underperforming this year was an anomaly.
Edited for formatting purposes.