[jsmeaton]

> An employee really worth it will see their salary go up.

Maybe at some places but I'd bet not at the vast majority. An employee that is worth more than they are paid will sometimes be given a raise that was not asked for. The employee may also ask for a raise and either be denied or accepted. Lastly, the employee may look elsewhere and be recognised for the new value that they can bring.

Of the 3, the last option is what I've noticed much more often. This isn't (always) the "fault" of the employee, but of the employer unwilling to recognise or pay for the value being delivered.

I imagine the thought process goes "they are delivering X for value Y, why would we give away our profits for value Z?". But just like companies that need to demonstrate profit growth, the employees will want to see their own profits grow especially when their experience should lead to increased value delivered.