A few thoughts on this:
1: New gun owners doesn't necessarily mean new gun people/gun nuts. My grandpa had a .22, a 30-30, and a SxS 12g on his farm. We found a box of ammo for each with a few shells missing from each. My great aunt owned an M&P .38 that lived in a shoe box just in case. Neither of them would be considered gun people, and had they been in modern times, wouldn't have been on forums. Guns were just a tool they had for blasting random crop eaters or repelling theoretical burglars. Similarly, a lot of the new gun owners I know will likely not even put a full box of ammo through their pistol or rifle, shooting enough to say they've shot it and putting it away. We're seeing a lot of people returning to the idea that it's good to have a gun just in case, and that doesn't necessarily lead to them getting into it as a hobby, nor posting on message boards.
2: Forums like this are an old idea. I'm 30, and friends even a couple years younger just never got into them. Reddit, facebook groups, youtube, discords, all take the place of forums unless you started using them when you were younger or if you're into things like this where the older users tend to hold most of the knowledge.
3: Gun forums got real, real bad over the course of COVID. Lots of social media got worse, bordering on all, but man oh man try checking out the popular gun forums now. Conspiracy theories, insane politics, any negative "ism" you could want. S&W is an oasis in comparison.