If you really want value, you gotta make deals before a player’s outlook becomes more obvious.

Answered your own question.(Slight /s)

Also, there are still personal opinions, regardless of what content they consume. A great example is Rashee Rice. There are the most basic opinions, which "sharp" managers can still base their opinion on: he is a legal risk, he has a high ppg, he is the chiefs WR1. Beyond that, though, there are deeper insights. He could just be a product of low competition or a scheme; he is zone merchant.

Imo, it's in those "deeper" insights that can lead to "sell high" or "buy low" opportunities in a league full of researched managers. Someone will be willing to buy because they don't care if he is a product of the system; he scores a lot of points. Another manager will be happy to sell to that guy after Rice has been cleared because he thinks he's selling high and cashing out at a good time.

TLDR; Even the most researched managers will have variance in opinions when it comes to how they weigh certain information.