The past is always moving and disappearing. Old servers die, content is moved to new structures and lost along the line. That's why the wayback machine exists.

The past is always moving and disappearing. Old servers die, content is moved to new structures and lost along the line. That's why the wayback machine exists. Also, google is just a window, it's not the whole world. And for some years now they limit their crawling to the last years of content AFAIK, for multiple reasons. Over all, I think this is good, because it's more likely that old content is outdated and wrong. But of course old content can also be valuable. So for this stuff it might be better to use other ways than google to find them. Like searching directly on the websites or in specialized archives-search engines.