Mark Seemann explains why we need young people in the software industry:

We need young people in the software development industry. Because of their vigour and inexperience, they’ll push the envelope. Most will fail to do the impossible, but a few succeed.

And why we also need old people in the software industry:

We need old people because they’re in a position to speak truth to the world… Old people have less on the line, so they can speak more freely. If someone you used to admire retires and all of a sudden starts saying or writing unpleasant and surprising things, there might be a good explanation, and it might be a good idea to pay attention.