[TechD00d]

If someone is that essential, it’s not hard to go from “at will” to mutual 90-day notice required. They want to quit, they must give 90 days’ notice. You want to fire them today, you still have to pay them for 90 days (including health insurance and other benefits).

People want things both ways. They want the flexibility of at-will so they can drop someone immediately, but they also want the employee whose work will make them very wealthy to be “committed” and “in it for the long haul.”