I think it has more to do with the "season"/sport, so, football should be there, as long as the leagues are the known ones, like you did, in placing the main leagues.
On the other hand, the event you organized, thank you for the invitation, must have "exploded" but let's say that G & R is not a place where one would expect a lot of influx if an adequate promotion is not done, there is always a fixed frequency of participation.
With that said, it's not so much about where are you from, but more about the season-sport is going on, right now there's the Australian Open,then, for example, baseball starts in April, and there is no participation, the NFL does not attract many users either, perhaps the NBA because it is more commercial than the previous ones and because, like football, most countries have leagues.
So, I would prefer to do proper promotion and invitation management, however, the sports, if it is important, but without promotion, the "customers"(users btt) do not arrive.
If you do something, keep the OP updated, there are threads/sponsors/users here, gambling board, that organize "things," and sometimes if you are not up to date with their topics, you can miss certain info that one could participate in, so, there are few users who update OP.
I have an abandoned thread in that sense, which I started with that idea, but keeping it updated requires that type of thing, finding the information easily to disseminate it. I mean, I'm being what I criticize
I hope you can successfully organize your next promotion. It wouldn't be bad to include a sponsor...
Hasta luego, fM.