Lightguns don't work on LCD screens, so they were not feasible on most consoles once folks started swapping out their CRTs.
Wii had a handful of light gun like games (that used the sensor bar of course) with the Wii Zapper, but other than that games of this type have needed more niche peripherals (Kinect, PS camera, now VR) that have made them more niche.
Right, but "just use cameras" is what I mean by "niche peripherals."
Other than the Wii, no modern consoles have had an installed user base for Move/Kinect/Camera type stuff to make it worth it for many developers to get involved. And even the Wii was just mostly shovelware waggle games, though as I mentioned there were some Wii Zapper games that approximated lightguns.
I think at this point we're past the sorts of external cameras and tracking necessary for lightgun things even more than we already were. This sort of stuff has already moved to VR and I don't know that we're gonna get them back in the physical realm any time soon.
You could easily do it with a Switch controller shaped like a gun and nothing else. It's pretty accurate on its own right, just using motion sensors aka accelerometers. I'm not talking Kinect because that watches you. Completely different concept, though you can do it that way too. Cameras that can scan TVs a thousand times a second to look for moving images are a dime a dozen, not exactly expensive anymore. Maybe 10 years ago, but not today. It does all boil down to money though. Maybe they think those type of games aren't popular anymore, so not enough return on investment?
People don't want to buy a gun to play 1 game, and that seemed to happen often even back in the day with light guns.