And don't academic people want their work to be read? Isn't that the point? The reward is the data and info their collect in the course of their studies and experiments. It's the prestige, and possibility that their prestige and acknowledgement will get them future funding for their future research. That's my understanding at least.
They do share the information... with those they want to share it with at the conferences where they present their findings, in the journals where their papers can be found by like-minded individuals to read. And if they want everyone to read them, they would put it up on their personal web pages like many of them already do. If they want their work to be free, they're perfectly capable of making it free without issue. You can't take their work and decide for them.