I'm a firm believer that football analysis shouldn't be some binary, black-and-white thing. Numbers matter, but so does film. Josh Allen's potential to bust is high because of a low college completion percentage, but Josh Allen can still work out at the NFL level.
So let's not oversimplify things: it's not that running backs can't matter, it's that it's hard for them to matter consistently.
There have been countless studies done on the true impact of running backs in today's NFL. This is certainly not the first one. This isn't even the first one that I've done.