This is more of a reply to the question, why write new songs, rather than sing the great existing ones? But here goes.

We all need to live in a house of some description.

Some of us move in and leave it pretty much exactly the way we found it.

Some of us have to change it around a little before we move it

Some of us need to build our house exactly the way we want it, from scratch.

The end result may not be generally thought of as the very best architecture but it does suit our purpose.

After it is built, it is also nice when others would like to move in and leave it pretty much exactly as they found it....