Disagree. Devers isn’t a leader; it’s not in his makeup. Not everyone is (I am certainly not one); no sin in that. The FO was stupid in assuming he could be one.
In a way, Devers is a bit like Yaz. They are introverts who, their given their druthers, would rather be left alone to just go out and play. Yaz very reluctantly accepted the role, but he wasn’t comfortable in it. Devers had the additional barrier of language, but I don’t think that played a big role. He just didn’t want the role.
BTW, Betts was the only one of those players traded. Bogaerts reached free agency and Eovaldi left the Sox twice via free agency. Betts would have as well.