Every Nostr dev has to re-implement the protocol themselves, as well as login (which isn't easy; OAuth is a quite sophisticated workflow), data storage, security, etc.
There are prefab components, but there aren't *Nostr* prefab components–at least, not many. I'm sure more will come as the ecosystem matures.
Kudos to ‘NDK’ and ‘nostr-tools’, but even these are hard to keep in sync with fast changing NIPs and ‘best practice’ environment.
If someone creates good, reliable, widely-used Nostr protocol libraries, like NDK and nostr-tools, those will be the de-facto spec. There are benefits to a high pace of innovation, but not everyone wants or needs the latest NIP the moment it is proposed.
Perhaps a monetization model is for the free version of an app to use the "old" stable NIPs, maintaining a broad base of compatibility, while paying users get to try out the latest and greatest protocol updates as soon as they are implemented. Those paid users can also give early feedback and/or request features.
