I get your point, but one thing I just checked after reading your post was the progression portion of the blog. It doesn't actually say anything about in season progression. It seems to imply an end of year evaluation where baseline progression either goes up or down based on player rank in the context of his same age peers.
If that's the case, then progression is an end of year change just like assignments of roles. In season progression or regression is, in this scenario, more akin to a fluctuation based on performance with the baseline attributes and OVR as the starting point.
Now, in my CB example, maybe my cold streak #1 CB is 30 years old and I have two guys behind him with decent potential who are younger. Maybe then I risk seeing him get stuck cold and play fewer snaps while I invest snaps in my up and comers. Ok, I get that part.
I guess all I really want to hear is that better play can cut a cold streak short, or worse play cut a hot streak short. And I'd like to know if stable, consistent players not only have more shallow streaks, but can maybe have streaks of shorter duration. Because in the real NFL, some players can come back from an off game better than others can.
But I get what you're saying.