1. With most arcades shut down, people that grew up playing in one now have disposable income and recreate that experience at home. Games that you loved dumping quarters into you can now fulfill your adolescent fantasy and buy one.

2. Virtual Pinball has stroked some of those old fires and created new ones.

3. People are being reintroduced to pinball and arcade machines by going to shows. It is not a coincidence that the popularity of shows have increased the same time as the pinball resurgence. Every show that I have gone to has gotten bigger and bigger each year with new faces.

4. It is a hobby that has more than 1 facet. You can play, mod, tinker, trade and collect. It hits on multiple levels.

Good questions that leads to the half empty/half full perspective.

Is pinball all the way back to the early 90's?
No, not even close. 20k TAF built in 1993 ends all arguments.

Is pinball in the same state it was 4 years ago?
No- it is much better. Without having Stern's production numbers you can still see that it has grown. They have rehired and expanded staff versus the layoffs they had to make a short time ago. There is also another manufacturer making 50 pins a week with other small boutique shops popping up every day.

There are more shows emerging, again not as many people being exposed to pins as the hey day of the arcade era, but still a lot better climate than 5 years ago. Plus you are seeing more barcades emerging, Hall of Fame venues being planned, and cottage industries (modders, suppliers, part makers) revolving around the growth.

The hobby has gained in popularity, just not to the heights of pinball 20 years ago. The OP has a good question when wondering why the growth.