Blandino was ASKED about a reach by Rich Eisen.
Right, and that was Blandino's perfect opportunity to say the reach didn't matter, if that had been true.
So why didn't he?
In the tutorial video "Explaining the Calvin Johnson Rule," the whole purpose of that presentation was to educate people on how "going to the ground" works. And in that video, he says a reach is an act common to the game that shows the catch process is completed and makes the player a runner.
If you want to know how such plays were ruled at the time, then refer to Blandino's tutorial. Case book plays aren't a comprehensive list of all possible scenarios, as you already know, so they don't prove a negative. That means you either have to find a case play that says a reach was
not an act common to the game that could be performed while the player was falling, or some proof that the NFL said that.
The case book play being changed from a lunge to a reach is interesting, given the timing, don't you think? If the newer version of that case play had been in the book in 2014, that would have justified the overturn, but it would also have contradicted everything Blandino was saying at the time about a reach being an act common to the game that completed the catch process, even when a player was falling.