You can’t just let disengagement be. You have to manage it.
It’s easy to manage motivated people, people you like to work with, people who are talented and constantly deliver good work. It’s more challenging to manage those who are disillusioned, who have have little ambition and feel out of place, who end up meeting all requests with silence and a nod.
And you can’t just let them be. Because disengagement spreads and it touches everyone it meets.
It’s likely that disengaged people will end up leaving. It’s your responsibility to manage the transition. To ensure they get the best deal out of it. And to ensure that they don’t leave disengagement behind.