I think it is clear the rainbow is the Dodgers where they have a rich farm system but can use their financial hammer too. The Dodgers and the Red Sox indeed are both using Tampa Bay organizational best practices.
Really, ownership probably gets the lion's share of the blame - not because Henry did not spend money, but because his organizational priorities have fluctuated wildly and at times seems way way too responsive to what talk shows say about the team. After all, the team greenlighted David Price, a deal which went poorly (even acknowleding Price's yeoman work in the 2018 postseason) in some somewhat difficult to anticipate ways (his arm). Ownership greenlighted the Sale extension, a deal which looked shaky as it was happening. At the same time, the team gets weak kneed about paying a superstar for the superstar's superstar years - and then moves him to help get rid of Price.
I largely don't blame any of the GMs - they have all done jobs that ownership asked of them. Dombrowski drafted well and did a good job - and he did exactly what ownership wanted him to do. Bloom has done a nice job making some good value signings and bringing in more quality arms than the org has had in a while.
Cora is one of the league's best managers - but when you have to negotiate "Eovaldi, a Pavetta hot streak and hope" as your starting pitching, you can only conjure up so much magic.
But still, his era will come down to ownership priorities. If the team is not willing to pay Devers superstar prices for his superstar years - a team with Boston's $$ heft - then what are we doing here.