It take a lot of the fun of quitting if there is an infrastructure involved. Because, if you did good work, the new guy can coast for a while with doing less work, spending less money, and being less of a pain in the ass to the powers that be.
Until the lack of maintenance and the added cruft finally brings down the system -- whether it is a machine, a code base, or a properly set up sound system. But by that time they will have long forgotten you, and management can make up other self-serving excuses why they are forced to go back to spending money and taking what seems excess time and unnecessary concessions.
(Another frequent scenario is when the gear is old, management refuses to authorize any upgrades, and you spend way too much of your time in repairs and patches and work-arounds. Until a new guy shows up via social circles and dazzles them with "unlike your old hire, I am a professional." And the first day on the job, they are upstairs complaining; "How can a professional like me work with such outmoded equipment?" And the stuff you wanted for so many years gets bought for the new guy.)