You're kidding, right? Being surrounded by empty platitudes with the expectation that they'd motivate me would serve only to demotivate.

Try giving your developers responsibility, autonomy, trust, and respect. You'd be amazed how far a little self-determination and native pride in ones work can go.

And if your developers are incapable of handling autonomy or have no particular desire to take pride in their work, your problems run way deeper than motivation.