Honestly, Discord effectively killed off a lot of forums. I've seen a lot of places firsthand that suffered heavy defeat and eventual shutdown because Discord basically centralised niche communities that previously had a combination of forum+IRC.
Apparently they're a Web 1.0 relic of the past, but honestly? Web 3.0 is garbage, promotes 'short-term' content and pandering to SEO and corps to manipulate the minds of others for that tasty Google Ads rank, and the amount of offshore resources that seem to get preloaded on every single modern website is... absurd to say the least.