Is Mathis an upgrade from what we know about the folks we have today - YES!
However I believe there may have been 2 issues at play here
1) Chip's ego/ need to show how much he values the culture he is trying to instill
2) Rosenhaus shenanigans. Mathis may have wanted what he is saying now and nothing more, who knows how Rosenhaus presented it?
Will never happen, but best case scenario for the Eagles - Mathis fires Rosenhaus, comes back to Eagles. I think Chip has shown he is willing to pay for leadership & performance