Pool on the other hand, you get a Fargo just by entering a lot of tournaments or leagues
While it might be more likely for a pool player to have a Fargo rating, I still think the majority of pool players don't. As an example, I've been playing since the early-to-mid nineties, long before Fargo existed, and I didn't have one until under a year ago.
APA and a few other leagues don't report. There are plenty of tournaments that don't report. And, of course, lots and lots of casual play doesn’t get reported.
I think the existing Fargo ratings are still skewed by selection bias since most who would have a score are already enthusiasts to some degree.