I’m gonna bet there’s more like 4-500 million guns out there.
I'm with you. What is their statistic based on? Gun Sales? Dating back how far? I have family that has weapons passed down across 3 generations. Model 1870 Winchesters, M1 Garand, 1906 Entfield (?), etc. Most of them shoot just fine. I don't expect my relatives admit to having these firearms if surveyed. They would only mention the ones they purchased and keep.
I don't have many but own more than I talk about or would offer if asked. I doubt I am much different from most other gun owners.