For any enthusiasts that want to start a business future location model with the "history of pinball" in mind, not just a simple route with a couple of games and do a few pulls:
It takes months of training to properly train coin operated technicians, years if specializing in dozens of types of game manufacturer systems, not considering EMs. EM technicians with the propensity to handle large amounts of game titles are rare today with both skill and experience. They just are do not exist due to the age of the games. Some companies outsource some of their operations due to specialty. These type of people you cannot just "hire off the street", because they simply don't exist anymore like they used to 20 years ago. Talking EMs with modern technicians is like speaking Swahili. BTW, the salaries of technicians are not "amazing" either, so you are not going to lure the few left away from other operators. Tough luck depending on where you want to open that location!
Some of the minimum periods for reference. A basic training curriculum for a coin operated technician is six months. Bench tech one year. Field technician 2 years with some supervision, but it depends on the aptitude of the worker and the skills they bring prior to employment. If a person is "average" in learning, double the length of time. If a technician is being asked to service all types of games starting say from 1960-2018, lord almighty they better have worked in the industry before.
A good example of this whole process is how painful the PHoF came to be, and why it still has problems today, but that is a different story.
Learning how to clean a game versus properly non-hack and troubleshoot a game are two distinct differences.
Just like home use restorations versus route preparation/maintenance operation.
Any potential new company that thinks they can do it "on the go", and figure it out later, are already in a state of confusion with no plan, and ultimately a very high chance of failure.
