Nintendo hides them really well from you but there's a menu options to go look for updates. My two 8bitdo controllers get quite regular updates, they have their own update tool for it.
Most things that are powered have microcontrollers in them these days, and that usually means firmware of some kind - it's not always "field updatable". A product I was involved in the development of used a fairly standard li-ion battery pack, and part of the manufacturing process involved making sure the firmware on the batteries had been updated correctly
All new (first party) controllers have firmware updates these days. Sony has almost identical prompts and used to require you to plug them in via USB to update before they eventually figured out how to do it through Bluetooth. Even PS4 controllers going back almost 11 years now used to prompt for firmware updates from time to time. And Switch controllers will update as well, but usually very subtly.
I wish.... Very tempting to completely wipe my Xbox and install a Linux distro (Arch obviously) but there's just a few games that I can only get on Xbox, plus the multiplayer aspect of the few remaining local multiplayer games.
For Steam Deck users, my Xbox controller worked like shit on it until I updated it, but to update it I had to use either an Xbox (didn't own one) or a Windows computer (also didn't have one), so I had to borrow a mate's laptop just to update it and play some multiplayer games.
Steam deck has the best controller built in. Why go through the trouble to use an inferior one? If I'm playing with friends, I can just connect my steam controllers.
If that surprises you wait until you learn what happens if you have an Xbox Controller and do not update the firmware for some time. It might just start crashing your window manager (component of the Windows operating system) at random times for some reason and the games you are playing just suddenly minimize one or two times per hour.
Have I mentioned I try to use Linux wherever the software I want to use is available for it?
Yes they can, and I updated it mine, which I bought only to play with my Android phone (I don't have an xbox) and then Call of Duty Mobile didn't detect it anymore.
Obviously speaking specifically to the case of a controller here (whereas the typical had been a fixed product that more or less functioned as expected for a lifetime).
"New features" is meaningless drivel on its own... what are the "New features" that can and have been delivered to main platform game controllers solely from OTA firmware updates? What are the bugs that have been fixed, specifics amigo...