I see more Nintendo threads than PS or Xbox in general.

For starters, the Switch has been out for 3 years now. People already know what it does, and more than likely own one, so what's there to talk about at this point besides a potential "Pro" version. There's also the fact that the Switch isn't really in the "Next-gen" battle. It's really its own thing, the next-gen battle is really between Sony and Microsoft.

Because... this console's over three years old!

Amazing, but not recent

Because the OP stated something as fact, which I cannot test, I went to Google Trends: https://trends.google.de/trends/explore?q=%2Fm%2F0130pygf,Playstation,Xbox

The result is kinda surprising. While Switch and PS are on a somewhat similar level, search for Xbox is much more strongly. I don't exactly know. Interpret this datapoint however you want, because I don't really understand it.

I don't think Nintendo competes with Sony and Microsoft anymore. It could be like two people discussing if they are going to buy phone A or phone B while expecting to hear about tablet C in that discussion. I mean, they are somewhat similar but you can buy a phone and a tablet without it feeling redundant. I have absolutely no data to back this statement, just a thought.

The Switch isnt really part of the next gen to many. Its just its own thing. Same reason why people dont talk much about mobile gaming either when discussing these things. Its been like that since the Wii for Nintendo.

A large portion of Switch owners are below 18 years old and they just want to play games. Social media engagement about console war is a waste of time for them.

I see reports saying Switch has a higher female userbase, but never find anything about age groups

Regardless, I'm sure your assertion is equally true for both Sony and Xbox owners 

Apparently videogames are for kiddos... main demographics globally in the US:

• https://www.statista.com/statistics/189582/age-of-us-video-game-players-since-2010/

Nintendo data discussed here on VGC:

• https://gamrconnect.vgchartz.com/thread/232587/nintendo-switch-owners-are-mainly-male-age-20-34/1/
• https://gamrconnect.vgchartz.com/thread.php?id=189255

More recent estimates:

• https://www.gamesindustry.biz/articles/2019-02-11-eedar-nintendo-switch-attracting-more-women-wider-age-ranges-over-time
• https://www.resetera.com/threads/nintendo-shares-gender-and-age-breakdown-of-us-switch-buyers.2852/

Isn't the younger generation *more* involved in social media?