I never had to change a dead battery on my analog depth gage or SPG. My last SPG lasted 30+ years with one spool valve replacement. Any PDC out there 30 years old and still working? No, and there never will be.
I have no idea if current dive computers will still be working in 30 years, but I don't see why most of them wouldn't. Most people replace their old dive computers because they want new models with new features, not because they physically wear out. And while some people assume that digital devices are less reliable than analogue, I haven't seen any ACTUAL data regarding the reliability of analogue vs. digital. I accept your personal experience of no problem with your analogue depth gauge, as long as you accept my personal experience of the reverse (with one serious SPG failure), and realize that they are both single diver anecdotes. I buy gear that is the best tool for the job, not because I want to make sure that I will never have to buy another one again over three decades.
The downside of having a PDC over a depth gauge and timer is that you have to keep the battery working.
The upside is that virtually every diver gets more bottom time on a given dive (since most dives aren't square profiles), that it records your actual, exact profile for logging and accident analysis. It knows what you actually did, not what you thought you were going to do ahead of time, or gusstimate during the dive. It lets you sync this data with an electronic dive log, which some people like. It makes it easy to recalculate your N2 loading on the fly if your dive changes for any logistical reason, based on what you actually did on your dive so far. It tracks your ascent rate in case of inadvertent violations. And it lets you adjust accurately for personal fitness and/or risk acceptance, which you really can't do with a table.
The vast majority of divers today chose to use a PDC because of these advantages. It's fine to stick to analogue if that's what you like, but I don't see how overall it's better in any way. I'm sure that you know all of this, but just making the point for any new divers who might be reading...