And the prompt doesn't save you there either, not sure what the best solution is.
Discussion
Being able to export your follow list and pushing to the relays?
The best solution is Event Sourcing: don't make a replaceable state, but a list of add and remove events.
Had the same thought.
Wouldn't the issue then be needing a full history of events to recompose the state?
Why not keep a history locally? You could do the prompting or not -- but even then instead of overwriting you still keep the previous versions.
I do like that Gossip keeps a local copy and only overwrites -- or merges upon an explicit button click: 
Someone should also just host a metadata archiver relay that stores all versions of everybody's metadata (by just querying other relays) and then offer a metadata recovery service. Maybe #[0] from https://erdaltoprak.github.io/nostrid/.
I imagine that losing follows and whatnot won't be an issue for people that only use one client, right? And then once you're using multiple clients you should also be open to using a dedicated client just for managing your contacts and so on.
#[9] already keeps metadata history and allows to check it on https://nostr.band .
Maybe it could add also the Contact Lists?