Feels like a lot of that is the Pats ownership, Kraft, getting old and wants another championship. It's usually not the coach dictating spending but the owner-GM.
I think
KDawg nailed it with their early success hurt them more then helped. They felt they we a game away from the SB so they don't need to be that aggressive -- they can sign veterans on the cheap and work FO without going for the kill. But that approached backfired. And they are still dealing with the backwash from that off season.
Also the narrative from 2024, that Jayden can overcome any bad roster - bad defense, meh WRs, no problem.
Felt like they thought they found a cheat code. And IMHO they got arrogant with this approach, lost their edge and man have they paid the price for it.