Matt Winkleman noted that too (and wasn't happy about it). I thought it was more of a throwaway observation myself, but it's hardly a surprise. Essentially Joe and DD both answer to Middleton, and yes, appear to be on the same page. The replacement theory is not uninteresting though.
I can't say I'm optimistic about any of it, tbh. It seems like they are heading for a classic overreaction despite the lip service being paid to multiple approaches/POVs. The short-term future - i.e. the possibility of actually playing in a World Series under Girardi in 2022 or 2023 - still does not seem bright, and the likelihood that Dombrowski leaves behind a Top 10 farm system and future contender also seems remote (especially if there's no active rebuild period).
I think hitting and pitching coaches are almost never really the problem. It rarely seems to help when changes are made. Nobody seems to be calling for Juan Castro's head either but hasn't his department been an even bigger failure?
That said, Girardi has also been coaching with Kapler's staff, for the most part, and I wonder if it's just time for a few new voices. The Phillies hired Thomson because they thought Kapler needed an experienced hand and he was Girardi's guy before that, but I'm not seeing where they are an especially distinguished game-management pair.