From the point of view of the manager, I agree (you need to proactively make sure the people you want to keep are happy).
From the point of view of an employee, I disagree. If you are contemplating looking for a new job, then you are unhappy. If you are unhappy with your job, you should at least try talking to your manager. Either:
A: They want to keep you and are reasonable and capable of making the adjustments you desire
B: They don't want to keep you
C: They aren't reasonable
D: They are not capable of making the adjustments you desire
In the event of B they don't want you to be working there any more, so look for a better job. In the event of C or D, you probably don't want to be working there anymore, so look for a better job.
That makes it really easy to reject a potential counter-offer; if they won't give you what you need without you threatening to leave, you probably don't want to work there.