I miss being able to pop open the little bay on the back of the Saturn and replace the CR2032 coin battery. I think maybe all the systems after that (well, some of the 6th-gen systems at least) switched to rechargeable batteries? I think at least the Dreamcast did. After that I stopped paying attention, cuz systems from 7th-gen onward regularly connected to the Internet, and the time/date would get updated that way. In any case, if a Saturn has a dead battery, you can still use it just fine. You just have to set the time and date every time you turn it on (if you even care to do so), and you won't be able to store save data on the internal memory (but you should have a memory card or something like the Action Replay 4-in-1 anyways).
As someone who keeps and uses their systems for life, I wonder how usable my PS3 and PS4 are gonna be 10-20 years from now. I was pissed off about games on Switch cartridges not containing the full game on the cartridges (cuz the devs cheap out and get the smaller-capacity cartridges), which might be a problem many years from now. If I can't even play physical PS4 games in the future cuz of a dead CMOS battery, that would be some BS. I got into my PS3 easily enough (had to swap out a dead blu-ray drive), but I don't know how easy it is to get inside my PS4 Pro, or what kind of CMOS battery it uses.
In the end, modded systems are always the answer, especially for enjoying systems waaaaay after their time. No more bullsh1t restrictions (like how Nintendo Wii won't let you backup some save data), and full control over the systems (like being able to control the system fans in a JTAG'ed X360). If a stock PS4 is nigh unplayable in the future, a soft-modded one will do the trick. The community always has an answer. See the work done to make Capcom CPS2 and CPS3 arcade systems fully playable in the modern age, getting around their stupid-*** suicide battery DRM crap.
