I'm not sure. I think this is a very absolutist and probably naive way to look at it, frankly.

For a simple example, let's say you use an immutable data store. What do you do if a customer wants every info about them redacted, but you did something like store their IP, name, or email. All common things. Now you must build mutability into your store and all assumptions that used to be made can be removed.

This is just a very small piece of something that even a small or medium company may be using or doing.