As we innovate exponentially faster and have better tools and languages, it is far easier to tear the building down and start over.
Also, I don’t know of a single app I use regularly that is older than a few years.
What did you use to visit this website? Check your email? Open a spreadsheet last? If your a software developer, what do you edit code in? Your operating system?
Hard to believe you're using apps less than a few years old for any of those much less all of them - or even those that are by name older but have been through a Big Rewrite in the past few years.
Mutt - July 2020
Gnumeric - August 2020
Vim - December 2019
OS - Ubuntu, April 2020
They might not have had big rewrites, but they are still under active development (I actually run slightly older versions, but nothing older than 5 years)
The code I use which isn't under active development is stuff I wrote years ago, but showing its age -- one uses flash to deliver video for example. Last update was a specific view for a blackberry, which gives an indication on the age. That view didn't support video as we didn't have 3G in the fleet.