There are employees who's retirement is based on their earnings (or pay grade). This is true for most government employees, military, civil service. I don't know about how pensions work in the private sector.

Additionally, more earned income means you contribute more to social security, which can translate into a bigger ss payout in the future.

With that said, and depending on a retirement system, more money will probably mean a higher pension and more social security at the end of the line. That is pretty important. So it certainly can be a highly motivating force for those who have a very long view, have mastery over how their pension is figured, and are doing hard core, realistic retirement planning.