[kupfer]

The professors I know are experts in their small domain (and most of them are really smart, but this is not my point here). They know all the nitty details, I am always amazed by their wide knowledge in discussions. I think for a society it is easily worth it to pay people to dig so deep into their field of interest and the market is not the right mechanism to enable that. I also think Youtube is nice to get started, but I found it insufficient for graduate level material.