What is a simple system?

from blog Marc Brooker's Blog, | ↗ original
What is a simple system? Is this pretentious? Why do I need cryptography when I could simply hide the contents of my communications rotating every letter by 13? Why do I need a distributed storage system when I could simply store my files on this one server? Why do I need a database when I could simply use a flat file? Do any of those things, and...