So, all you have to do is replace the battery and connect to PSN once? As long as some form of the PSN exists, you should be okay?
Yes? This is assuming old PlayStations won't be cut off from servers. Still, physical games don't have the same value they once had.
While this likely only affects a relatively small portion of the user base (again, I expect the vast majority to move on to new hardware), I imagine most people don't know this is a potential issue or how to fix it which Sony is likely counting on. Sure, one can google it, but there's also a reason why LMGTFY is a thing.
It should also be noted that the CMOS battery for PS3 and PS4 is directly on the motherboard so you would have to open up the console to access it. How many people have a Torx screwdriver? Few people know this is an issue and even fewer people have the tools to fix it themselves. Comparatively, the CMOS battery on Wii and Wii U is accessible from the outside of the console. You would need a #00 Philips screwdriver which you may have if you wear glasses.
Regardless, what's worrisome to many is the implication that these games can disappear coupled with Sony's apparent disinterest in preserving its own history. While most of the bigger titles are available on the PlayStation Store and tied to a PSN account, there are also a lot of games "trapped" on those old systems so in the event that the CMOS battery dies and access to servers is gone, those games are unplayable (barring a hack). The ones I keep hearing about are the older Gran Turismo titles which will likely never get re-released due to the ungodly amount of licensed content in them.
I mean, this isn't ideal (and, in theory, is something Sony could patch at some hypothetical point in the future when PSN support is totally taken away), but it doesn't seem as world-ending as some are making it out to be.
One thing I've learned from working in IT is that fixing one thing can lead to unintentionally breaking a slew of other things. Removing the requirement to pull the date/time from a server is a really easy fix on paper, but it could create an exploit for hackers. And if it's a lot of backend work, no f-ing way Sony fixes this. There's very little cost benefit from the company's perspective (i.e. the goodwill of a small group of PlayStation owners). What are we collectively going to do about it? Stop buying PlayStation things? Given Sony's market position, it will call our bluff 100 times out of 100.
Again, I'm not trying to be alarmist. This absolutely is not world-ending. It's just kind of crummy because Sony didn't have to write its software on at least four different systems this way, and I'd bet it's the same on PS5. Nintendo's and Microsoft's hardware do not seem to have similar issues.