I disagree. RBs more than almost any other position transition from college to the NFL pretty seemlessly. Injuries are pretty much the only risk.

And part of the point is you can sign a cheap veteran in the event of an injury and keep chugging along as long as the now injured RB wasn’t your entire offense. Also, a lot of teams already have a veteran on the team for these scenarios, it’s how Latavious Murray has been making his money the last few years.

Which brings me to your point about the Jets. They absolutely struggled when Hall went down, but it’s not because the RBs behind him weren’t good. They actually played pretty well, but the problem was their QB situation was so bad that their offense only functioned with an elite running game. So in that sense, an elite running back can be valuable to cover up serious deficiencies in the rest of your offense (that’s what the Titans have been doing for a while), but RBs are prone to injury, especially older RBs (which most of the “elite” RBs are). So the only reason to need an elite RB is if your offense sucks otherwise. And that just means that if that RB gets injured, which is very possible, your entire offense falls apart.

This is essentially why RBs are being devalued. You could spend $18m on an elite RB (essentially what Zeke Elliot was made before he was cut), or you could spend that on an elite TE or good OL and pick up a mediocre RB for way cheaper and have a much more stable offense. Then on top of that, you can spend a 2nd or 3rd on an RB who will have a pretty high floor and could end up being elite.