This talk describes how an increasing number of the aspects of life are marketized, meaning they are being evaluated for their monetary weight and then private interests can purchase advantages in those aspects. He gives a couple of examples, which need no repetition by me, and these should be news to most people. They exemplify how a certain distortion is introduced by this take over. What Michael is trying to convey here, amongst other things, is the question of whether or not this change has impact on motivation in a positive sense.
Now I did a piece on motivation almost two years ago analysing the idea superficially and making some minor connections to other issues. But I think a relevant answer backed by scientific studies to the question posed above, is the one supplied by Daniel Pink in this lecture:
It is clearly stated that the findings seem to indicate that monetary rewards seem to give a sugary rush to completing simple and mechanical tasks, whereas the exact same rewards inhibt critical thinking in creative tasks.
So when Michael Sandel asks the question whether a monetary reward for reading a book is a good idea, science seems to counter-propose whether we think reading a book is related to mechanical or creative thinking. If we simply think it is about turning pages and memorising knowledge, then we are branding the reader a vessel for the knowledge of others, not an individual with creative abilities to process ideas and improve upon them.
And as Michael rightly points out - we do not know the long term effects on the motivation towards reading, if curiosity gets replaced by monetary goals as the motivator for reading and absorbing perspectives.
My guess would be: The sooner in life we introduce money as life support to people, the sooner we motivate them to stop thinking creatively and start thinking mechanically.