Quoted from CrazyLevi:

The best way to grow it is to do what YOU like in pinball and not shit all over people who like pinball for different reasons.
I'm a good tournament player, and I generally enjoy the tournament scene. I also like collecting mid-level to cheap games, working on them, buying them, selling them, flipping them, trading them etc.
So that's what I do. I play in tournaments, I put my own spin on booth commentary when I get a chance, and I've put together some modest tournaments as well as participated in putting on a large (and possibly annual) show at NYCPC. I'm part of the buying and selling community and I sell retail to many first-time buyers. Hundreds of homes have a pinball machine because of me.
Other people do other stuff best. Some make mods. Some buy or sell high level stuff. People restore. People run bars. People have websites. People do podcasts. People go out to local bars and play in leagues, or just drink and play pinball with their friends. Generally, it's all good.
There are some people who are convinced they are the only ones who have figured out why pinball is fun, and everybody else who does something different are at best misguided or at worst "ruining pinball." There are people out there who just HATE tournament pinball and I can't for the life of me understand why. I've been in pinball for 16 years, and for over 10 of them I didn't give a wet fart about tournaments. I never noticed the tournament scene AT ALL and had literally no opinion on it all as it had zero effect on my life or participation in the hobby - so I just don't understand that.
I don't really think anybody is ruining pinball. there's a very select few people who I view as parasites who contribute nothing, but I don't think they are actually detrimental to the scene.
The best way to grow pinball is contribute in your own way, as little or as much as you want.