No I think they picked the best player for that role like you said. But it wasn't part of the position it could be someone from any position and was something extra that shouldn't be held against a player at their position.
You make it sound like head coaches in the 1950's stood in front of their teams and ask "Hey, does anyone want to return punts?" I think that undersells the impact of the return game in that decade. Before you had punters going for hang time, special teams coaches, and kicking specialists, a team could get several big return plays over the course of a season. I don't think the Cardinals had Ollie Matson returning kicks because someone had to do it, I think they had Matson returning kicks because he was great at it and it really helped a feeble offense put points on the board. I guess technically kick/punt returns aren't part of anyone's position, not just RBs. Not every RB gets the same opportunities to rush and receive, either.
Now this is getting into the lack of accolades thing. Webster only getting elected to 2 pro bowls doesn't mean those decisions or any other accolades were right. We hope they are but we can see the stats and judge that ourselves. Arnett went to 5 pro bowls but his stats were worse in every non special teams stat. Webster had more total and average rushing,receiving and scrimmage yards. Same with touchdowns. But in terms of accolades it's closer than it would appear in terms of all pros it's 1 first team versus 1 second team. Furthermore the 2 played in different confrences and were not competing with each other for pro bowl selections. Meaning Arnett was not picked over Webster for those spots but over other players.I don't think it even has to be in terms of the HOF; it's how the players were viewed in their own era. Was Webster ever considered an elite RB? Jon Arnett's accolades dwarf Webster's. I think that is due in part to Arnett's return ability.
I guess this could be it's own thread. George McAfee is one. Paul Hornung wouldn't be in if he wasn't also a kicker and didn't play in the postseason. Doak Walker probably wouldn't be in without his kicking/returning/postseason resume. Frank Gifford might not be in without his passing and his defense. I would guess that there are several borderline HOF RBs who had the scale tipped in their favor due to something other than scrimmage stats.
It could be. With Doak Walker average wise his scrimmage stats are hall worthy and he's a Gale Sayers case(another one with good return stats). He's 2 games over that 65 longevity floor that seems to have been set. Also like you mentioned there's postseason aspect which is also important for McAfee whose return stats were better. But he was an all pro 4 of his 6 seasons. Regardless of the kicking and returning he seems to be in for his dominace on offense. I don't think Gifford is a borderline case and while Websters might be slightly better average wise Gifford had far better accolades and career totals.
The postseason thing I 100% agree played a role in many of these cases even if I think that shouldn't be how individuals are primarily judged. There's also the all decade thing, Doak Walker is really the only one we've discussed who isn't on the all decade team. If they're on the all decade team it seems that's there starting point for picking hall of famers.
Davis certainly deserved those touches given how great of a year he had. Just that those were the carries and catches seem to have went the following season. He was also a 1st round pick while Towler was a 25th round pick. And you're right they switched Tank Younger too, he was a great OLB but you wonder if they do that if they dont have so many mouths to feed offensively.
Towler was a rookie in 1950; I guess he could have touched the ball more, but Davis averaged nearly two more yards per carry and was a much better receiver. Davis spent a lot of time as a slot WR in 1950, so I'm not sure how Towler would factor in to that. If anything, what probably allowed Davis to take on a rather large rushing workload was the Rams using Tank Younger almost exclusively as an OLB in 1950. He went from 53 carries and 7 receptions in 1949 to 8 carries and 0 receptions in 1950 (but Younger was a great OLB).