Quoted from ForceFlow:
I know an arcade owner who has 80+ games, and 2 WPC-era pins. Pretty much all the games in the arcade need some form of repair or maintenance from time to time, however, the pins need attention on just about a weekly basis. Luckily, they have good documentation, and repairs are usually fairly inexpensive. But, because of the amount of maintenance they do need, and the potential expense of the unrepairable node boards, the owner does not want to take the risk even though he is interested in having newer pins. The pins don't earn a whole lot, they need constant attention, and new ones are fairly expensive compared to what they actually earn. Most other new games that he buys tend to pay for themselves in about a year or less. That wouldn't be the case with a new pin. So, he keeps chugging along with the older pins that have been long since paid for.
Same with the Family Entertainment Center on the east side of Tucson. Probably 100 games (and 2 mini golf courses, batting cages, bumperboats, go karts) and 4 pins. They get one new pin a year and get rid of the old one. Games are rarely worked on because only one person (manager) knows how. The rest are "kids" who just staff the counter and refill the ticket dispensers. Pins make less than probably everything, and require the most maintenance. If locations owners don't love pinball, it doesn't happen. I can tell you trying to keep 16-20 machines running in the wild is no easy task and I'd be better of getting a part time job if it was about the money.