Specific implementations - I think its too early, who can truly predict the success of any project? However, three main concepts I think will stay:

1) An interconnected ecosystem (you unintentionally sign up for nostr because you want a service, then look at that you've stepped into a river of potential)

2) immediate near-frictionless monetary contributions to the builders and facilitators of this ecosystem via zaps

3) Client agnostic users. Are you building anti features into your product that your users dont like? Users will go to another similar client. Incentives for user-adversarial features are reduced. Nostr apps encourage building with both other builders (keep protocol coherent and interoperable) and users (keep them happy)