Because things on the front page might have been pushed to page 2 by then, and things on page 2 might have been promoted to page 1, or aged to page 3, etc. The way it works now, all the ordering is fixed when you load the page 1, and page 2 will still be the same page 2 whenever you get around to clicking on it.
A solution would be that when your page 2 expires then you should be redirected to the most up-to-date page 2 rather than being told page 2 doesn't exist.
Comments
Because things on the front page might have been pushed to page 2 by then, and things on page 2 might have been promoted to page 1, or aged to page 3, etc. The way it works now, all the ordering is fixed when you load the page 1, and page 2 will still be the same page 2 whenever you get around to clicking on it.
A solution would be that when your page 2 expires then you should be redirected to the most up-to-date page 2 rather than being told page 2 doesn't exist.