IMO, part of the misconception in # passes to RB's may be because Carr dumps down so much to the WR (primarily in the past), which means he actually has/does throw a lot of short (dink/dunk) passes---but not just to the RB.
When a QB's ypa (yds per attempt) dips below 7, it's an indication that he throws short passes. Last year, Carr was below 6-against the Cowboys last week, he was below 5. Against the Jags, Carr completed over 73% of his passes, but his ypa was below 7 (6.6). A low percentage completion percentage with a lot of passes thrown can also result in a lower ypa but-IMO-may not necessarily 'translate' into a short passing game---
Overall, though, IMO, Carr is showing improvement this year. In Kubiak's offense, it's all about 'positive' yds. Rather than increasing the ypa by throwing the ball 'further' down field, it's all about receivers (RB/WR/TE) that can catch 'short' passes that can turned them into 'bigger' yac (yds after catch). Of course-to do that-you have to have that 'type' of receiver, and we have several.....and,of course, a QB-like Carr-that can make all the 'throws'...
And, as mentioned before by other posters, when the above happens-it opens up an occasional 'big' throw that stretches the field....