You are taking too big a leap on this issue. Keep in mind that the QB Collective needs to advertise so they are going to squeeze as much out of this as they can. That doesn't automatically mean that Brock didn't receive any coaching at ISU. There is a massive difference in training between a student athlete and a professional athlete. One trains between classes, the other spends the entire day at it.
There is a cost/resource benefit that college coaches must decide when it comes to athletes. No difference than when you see future NBA players spend years in college with bad shooting mechanics. Coaches only have so much time to work with players, and there isn't time to breakdown and rebuild a QBs throwing mechanics and still win games.
Maybe Brock didn't get enough coaching at ISU, I can't say one way or another. But you can't claim he didn't just based on how much better he got after leaving Iowa State.