This got me thinking about airgun folks that I know.I think you are off on that. Pretty much everyone I personally know who has a high powered airgun shoots slugs now. Maybe the majority who shoots low powered airguns don’t use slugs, but I’m willing to bet the majority of shooters using high powered airguns are now shooting slugs.
I'll just include the maybe 150ish guys I know personally. This would be the people I see a couple times a year at various matches. The folks I shake hands with and say "hey, how ya been?." Guys where I know what gun and ammo they shoot cuz I've been squadded with them at matches, and/or written match reports where we both competed. ie not simply online acquaintances.
The common denominator here would be field target, either high power or regular AAFTA. This is three different AAFTA clubs, and two different places that put on high power FT and/or EBR-like matches. I didn't compete at EBR last year, but I did the prior two years, so if you want to throw them in the mix we're probably talking another 25-50 shooters. So, call it maybe 200 people I personally have some sort of face to face interaction with, (ie NOT YouTube and airgun forums).
Of them, probably about half are strictly sub 20 pellet shooters. (one whole club of AAFTA type shooters is low power only, I think one of them has a high power pellet gun, no slugs. They've got 20-30 different people that come to sub 20 matches and don't attend any other matches anywhere else. ) There's a bunch of AAFTA shooters at the other two clubs that don't even own a high power gun.
Another quarter of that 150-200ish people are sub 20 pellets, and sub 100fpe pellet shooters.
The last quarter of that 150-200ish people sub 20 pellets and sub 100fpe pellets and slug shooters.
Slugs are definitely A thing in the airgun industry. But they're not THE thing. Despite what the retailers and influencers want you to think.