That's half the story. They are also no longer in a big boy conference, they are at the bottom of the pecking order in the AAC with some solid football teams ahead of them, and they won't be able to highlight major conference games or prestigious bowl affiliations on the recruiting trail. They are at the bottom, and need to claw their way up, which is no sure thing given their current situation, in its entirety. And all of those players you reference they put in the NFL were brought in several years ago by a coach no longer associated with the program, and the talent base anywhere close to the same as it was under the previous regime.
Diaco has no track record as a head coach. No offense, but I don't automatically make the attribution that he's a sure thing great coach just because he's at ND. It is much easier to be a bulldog recruiting ace at Notre Dame than it will be to recruit players to a mid-major conference. That's just the way it is. He could end up being a solid hire, but that is no sure thing--at a point when their football existence is teetering on the brink. Which is the point.