I'm not sure any of those were bad moves though. Knebel was disappointing but had started to come around before he got hurt, and Robertson replaced him. Kimbrel was actually good, especially at the price. But I wouldn't want to pay Jansen's salary ($16 million) nor give up much to get the Red Sox to pay half. Plenty of free agents still out there (including Robertson ha).
I would also like to think the Phillies understand that Kimbrel's preference for closing was not a great fit for them. He answered the bell when Alvarado got hurt and Seranthoy wasn't effective but I doubt they are actively seeking a 9th-inning guy