You're about there. We use all of our progress as a means to differentiate ourselves from other animals. We're smarter, better, etc. We have houses to live in

You're about there. We use all of our progress as a means to differentiate ourselves from other animals. We're smarter, better, etc. We have houses to live in and food to eat on demand. We want for little and don't have to worry about dying from a shark attack. But animals do seem to be generally happier. I think Adams succeeds on the sensible chuckle level rather than anything uproariously funny. He's just really good at sustaining it. You read it and go "Heh. Totally. Wars suck." So which is really more intelligent? Making an iPhone or just being satisfied with your life? The fish is a fish. It's a funny visual of seeing someone cram a fish into their ear and that's about as far as the joke goes. It could have been anything really.