People disappear and along with them their website hosting, or websites get taken down, etc. An excellent solution to at least finding the pages again is with the Wayback Machine Web Browser Extension installed.
If a page is not found the extension will prompt whether you want it loaded from the archive. You can also use the extension to quickly save any page you are viewing to the archive to have it preserved. I even have Wayback Machine's 404 handler on my website where a search page is not found, to offer to check the Wayback Machine Archives.
By opening the Archive you can also browse back time to see how a page changed from the past and the extension will also quickly search Twitter for any mentions of a page.
A web browser extension for Chrome, Firefox, Edge, and Safari 14. - internetarchive/wayback-machine-webextension