Encourage projects that are too big to be done alone.
Point out that the next level of success is going to require a different style than going at it alone.
When they complain that they (1) don’t have time and (2) other people aren’t as good, show them that they’ve crafted their work life so that no one can really contribute.
Coach them that real power comes not from knowledge but from networks and that there is more leverage in wisdom than in information.
Encourage them to manage using transparency.