Withholding was a powerful way of teaching. As the Chinese saying goes, When students master the knowledge, the teacher would lose their jobs. If teachers withheld what they knew, they would always be wanted. Because, in the old days, they were the gatekeepers of information, knowledge, and experiences. In the old days, all of those were scarce.
But the internet has changed everything.
Instead of scarcity, information is abundant. People can learn from various mediums and experiment with what they know. Teaching jobs have been transformed from gatekeeping to assisting positions such as coaching.
It is not a teaching job that is no longer needed, but we need a different kind of teaching. Just like in the world of abundance, information scarcity becomes increasingly obsolete, and so does withholding.