Pinball is today a tiny niche, and nowadays pinball players play at home. If you like pinball, you find all sort of information online. We are the pinball players. We have machines at home. Some people cannot afford it or do not have the space, but I do not think anyway people will start dropping lots of quarters again in pinball machines. There are so many other games available for free. People after the digital revolution want things for free, or anyway cheap. Yes the real thing is so much better than the virtual one. But still people do not want to spend decent amount of money in pinball. People with deep pockets interested in pinball, buy one. People with little money potentially interested, do not even consider spending tens of dollars in pinball machines. Or they get organized, and realize that its better buying a machine, play it to death, and sell it for about the same price. People obsessed by pinball spent a lot in the past, now they buy machines. So operating Machines you can break even at best, so its not worthed, unless you do it for pure passion. Its similar to certain music niche markets: producers, musicians just survive becuase of passion, but there is no real business there.
The only business left in pinball is building new machines and sell them to rich people to play at home. Or sell replacements, mods and tools online. Those are sound businesses.