Thanks for the kind words @PinballNarcissist.
Without a doubt, league play in our area has produced way more new players than any of our periodic events. Since you are playing every week, you are seeing the same people frequently. Eventually this turns into a bunch of new friendly relationships between people who would have otherwise not ever even met.
Even though I mostly started the league because I love competing, it has become overwhelmingly apparent that it is all about the people. I personally started out with zero interest in the social aspect of the hobby, but am now hopelessly endeared to the Cleveland pinball community. Thanks to a league format based on PPL and tons of good advice from people here like @joe, everyone in league is able to show up every week and have fun competing at their own level of skill.
At this point the community is strong enough that it is feeding off itself. The women in our league have held 2 “ladies night” tournaments without any prompting by myself which received extremely good feedback, partly because of elements created by them that I never would have included in my own events.
The league definitely produces more people for the periodic events but I would not say it works both ways. It’s a huge challenge to make every one-off tournament attractive for all levels. Even though it’s more of a time commitment, it seems easier and more appealing for most people to have something to commit to every week for a couple months. “On mondays I play league”. We also run on multiple days. Players may only play once a week, but they can play on any of the days they want week-to-week, which makes it easier for people with busy/chaotic schedules.
Not everybody wants to play competitive pinball every week perpetually, but some like myself absolutely do. For those people, I run a free knockout tournament once a week while we are between seasons of league. At the end of the year, the top 12 players in the cumulative results of those weeklies are invited to play in a championship (similar to SCS). The last 3 weeklies have averaged over 18 players.
Running league as an operator definitely helps. I’m able to be there to grab stuck balls and fix minor issues on the spot. I can choose games that I know to be good for competition, and maintain a rotation of interesting games. As a competitor I am super-sensitive about gameplay and set ups. This means everyone gets to play on games where I have obsessed over flipper alignments/software settings/slope/tilt/cleanliness/etc. This also means I can make changes week-to-week to ensure that certain games (Stern ST) aren’t playing long and causing people to wait around.
The popularity of league is probably the only reason I can “afford” to operate games at my small level. Even if I didn’t operate the games, I’d still be running events because I love doing it just like I was when all I owned was a broken Taxi with cabinet touch-ups that must have been done by a blindfolded kindergartener on PCP. But it’s definitely true that I work even harder to make sure my events are well-organized, inclusive, and fun regardless of skill.
In the end, the real reason any of this works is because of the strength of the community. Lots of people willing to help each other out in so many ways because we really love doing it.
TLDR; League has definitely been more effective at increasing event attendance in general, because it offers more compelling elements than most periodicals or one-offs. Running events/leagues as an operator is definitely a mutually beneficial situation.