Copyright 2005!

mail.google.com/mail/html/noco ...

It's because they didn't changed this page for 4 years.

If there is no technical changes happened why to update that footer text once a year?

If you don't change the page, you shouldn't update the copyright claim. Otherwise, the copyright expiry date worked out from the copyright date won't be correct.

Not that I'm likely to be around when the copyright expires on Google's current pages.