"... all their followers will continue to get his updates automatically ..."
Yes, but for this to work and scale in the long-term, Nostr identities (i.e. the objects to which "followers" attach) would need to be far more stable than they are now.
Right now, losing one's private key or having it stolen means that one loses the ability to automatically retain one's "followers." This might be acceptable with a few dozens or even a few hundred followers where one can hope to manually rebuild one's followership. But it won't work for, say, a few hundred thousand followers.
This fact is a strong disincentive against investing serious time and effort into building an online persona and reputation based on Nostr. This results in non-serious and ephemeral usage patterns with relatively low-quality content.
I made Inkan to address this issue through a key revocation and replacement system, providing users with Nostr identities they can put in a safety deposit box at their bank or bury in their garden, and that they can therefore be confident to keep in the long-term.
I'm conscious about promoting a product here. The excuse is that it's relevant to what's being discussed.