Ultimately, mining should be banned from the surface of Earth. Let miners build orbital solar panel infrastructure close to the Sun where power is plentiful. See Bitcoin developer Peter Todd's 2017-09-10 presentation on the subject (transcript).
Edit: Fixed URL. Edit2; Add transcript link.
In my opinion, it was when anti-trust laws did not trigger upon Google acquiring YouTube because Google Video couldn't compete. That meant it was open season on start-ups that otherwise might have grown to kill Google or other big tech companies like Apple, Facebook and Microsoft.