This fate has befallen all my machines older than 15 years or so. They won't turn on, or turn on and fail the POST, won't boot, whatever. Sometimes there's that fine smell of smoke being released accompanying the failure.
On the other hand, my Carver amp I bought 30+ years ago still works fine and I run it 16 hours a day, every day. It's the best, by far, piece of electronics I've ever bought when considering bang for the buck. The same goes for the Dahlquist speakers it drives.
Modern machines may be more reliable because of the lack of moving parts, but they have other disadvantages in the longevity department. Lead free solder and conductive glue will start to fail after a few thousand thermal cycles. (Conductive glue is especially used to bond flex cables to LCD screens and is not something you could repair yourself.)
If you replace the capacitor did you resurrect the dead or just fix a broken part? https://en.wikipedia.org/wiki/Ship_of_Theseus
My 486 machine was also dead, but I pulled out the drive and managed to find an old IDE interface on a 10 year old computer that would read it (after trying several), and copied it. (Turns out there was nothing interesting there.) The old disk drive was the only piece of old equipment I could get to work.
You can't do that with an iPhone!