Title is misleading. When I worked, my longevity pay was in my contract. It may be called a bonus, but it was an extra check that came in December and based on my years of service. Mine was a percentage. It almost always went to pay property tax, not christmas presents. I see bonuses as a reward for achieving goals and objectives of the work place. Not that you showed up to work a set period of years.
In the real world, adequate competence to do the job you were hired for is what gets you your weekly paycheck.
Not surprisingly, this "longevity bonus" fairy tale has only existed in public or private union employment.