Is it possible to export as a file, take that with you on whatever medium (eg. USB key, CD-ROM, future isolinear chip), put it on a brand new PC you built from scratch and never connected to the internet, and open it in some kind of standalone viewer?
Originally it was an app with no remote component. The vault was yours to look after. Most people kept it in Dropbox to make it accessible anywhere. The vault itself actually had an html file in it that you could open in a pinch that was able to decrypt secrets (only for reading, from memory).
1Password as a service came later.
Dropbox came later and security minded folks were wary. Honestly, I trust 1Password sync more than an encrypted db on a general purpose cloud file sync, but maybe that’s naive.
Super contrived, but you could probably just copy the sqlite dbs of your vault it creates locally to another PC along with the 1Password installer and it might let you sign in with just your master key.