Thank you for your in depth consideration!
Are we so sure there no perfect apps? What about crocodiles, sharks, tardigrades? They have survived millions of years. What about Skyrim? Why is it still so playable? What about UNIX?
Computers have existed since the first RNA code was made that happened to fold into a structure that "read" other RNA codes. Maybe this can imply something for web apps, how do we allow their code to replicate and mutate? Makes me think of forking in git.
I would focus on isolating anything that is likely to change from things that are more constant
Agreed. Going back to the genetic analogy, DNA replicates itself incredibly perfectly, it allows the "app" to be stable. Like english, it has redundancy so mispelsling a piece doesn't usually change it's interpretation. But some misspellings have huge effect. "Let's eat, Grandpa!" / "Let's eat Grandpa!" Expression is at the same time dependent on current environment. In a 10,000 year web app, maybe the coding should be partly "in the eye of the beholder (client)" and partly "despite the client".
Interesting stuff :) Thanks for engaging