I'm with the odd quine. In my younger day managers and employers were bad people. they demanded a days work for a days pay and if you challenged it or didn't do it you were out on your @rse and no questions.
If you worked hard the employer or manager would start to like you and coach you to better things. So hard work would pay off in the long run.
Nowadays team work and worker involvement is the thing. People are coached into taking pride in what they do. They are made to feel part of the system and to get involved in the decision making.
Unfortunately, between then and now, laws came into being that protected the disruptive or lazy worker from being shown the door and that is the one who can upset a whole team to such an extent that no amount of motivation will make a difference.
On one of Oddquines points though.....It may not be the responsibility of a manager to motivate but good managers do it as a matter of course. Reward and encouragement are all used to motivate. Anyone, in any field, should be giving what is expected of them for the salary they recieve and if they are in any way ambitious then thats what they will be doing and the pat on the back, the well done, the thank you is going to motivate them to do even more.