Apple discontinues products and replaces them with something else. Google's more in the habit of announcing a new service, saying it's great and revolutionary, then dumping it a few years down the line with a brief notice beforehand.

The iPod line just ended up superseded by phones. Google Wave, Google Plus, Google Code, Inbox (this one I'd get alerts for after every Gmail login saying it's the next step for gmail and I should switch... it just never happened), Google Video, Google Reader, and more just vanished.