As someone who has experience with a ton of forums(Discourse, Xenforo, vBulletin, Flarum) and other community apps like Discord, Slack etc, I believe the future of forums look something like https://circle.so.

I believe NodeBB would benefit a lot from learning from them! The idea is to not limit your user to one type of interaction but a modular system that allows one to communicate how they like and to adapt to all sorts of use cases where the sky is the limit(made easier with UI-based configuration and the option for custom HTML/JS/CSS when needed). For example, one wanting to make a cooking community would have a gallery view page for recipes that open lightboxes into the recipes, if they have a job board, one could use the gallery view or a minimal list view(no post counts etc), if they want real-time chat to talk about anything related to food, there's that option too. Feed view being another. Members-only pages where you have to login and many more.

Facebook does this quite well. By this, I mean the option to turn your Page into a multi-functional space where people could do more than just chat.

I'm aware that many of these features exist in the form of plugins, sometimes poorly coded or barely maintained. I'm thinking of a more built-in approach that is designed with so much modularity that it would not require plugins for the simplest things yet still being easy for the dev team to handle. NodeBB 3 and Harmony is awesome, and is probably my favourite of all forum software even compared to Discourse and Flarum but if you could push it in this direction I'm suggesting, I think it can be the leading software.

One good example of circle.so being well used is https://www.framer.community

If forums don't want to be made obsolete by software like Discord, I think it's the way to go.

Cheers!