Co-founder of solid here. I worked on Solid for 10 years before nostr, and founded and was first chair of the Solid community group. I worked for several years at MIT with Tim Berners-Lee to create the system.

But the realtime aspect was broken and no one would fix it. So I came to nostr, which was semi dead at the time. Even fiatjaf was not super active in the dev area. So we built up a small team that worked on making a usable system over the next couple of years, leading to the system we have today. Nostr replaces one component of solid. But we can also add all the other good parts, in order to complete the web project (though fiatjaf is somewhat against he web). Or we can add nostr to Solid. But Solid has lost a lot of users since the focus on nostr. I started work on solid-lite and nosdav to take the best bits of both projects together. It works, but I dont have as much time as I'd like to build them both out.