Niche communities being spread out across the internet in their own little forums and chat rooms is rare sight nowadays. Ever since Facebook started gaining popularity around the mid 00s, internet communities, small and large, started congregating in these massive media platforms. The aforementioned Facebook, Twitter, Reddit (alongside some other ones I might've missed) have largely replaced regular niche oriented sites. Such is the nature of the internet turning mainstream.

However, even if we were to put aside the ever growing centralisation of social / public-driven media, Bitcointalk always drew in a specific type of crowd when it comes to it's regulars (with a few exceptions) - hardcore cryptocurrency supporters. Hence if you are just starting to get involved in crypto or are aiming to reach a more casual crowd, participating here really doesn't make sense.

In addition,  quite a few people outside the forum have a negative view towards how the forum is run, be it through first hand experience or through stuff they read about it online. The fact that the forum's running on an extremely outdated piece of software (both design-wise as well as functionality-wise) has definitely turned some people off. The general lack of manegerial attention (fostering the community through events, some level of basic marketing, actively working on solving pressing issues such as sig spam) is definitely turning away both new and old members alike. The forum is growing every day and theymos (and to some extent Cyrus) can only do so much without any professional help.

Some may dislike theymos himself. theymos' ban on BitcoinXT on /r/bitcoin (as well as his subsequent comments on the situation) have left some members on Reddit (and 4chan) perceiving theymos as a despot who censors dissenting opinion. While there's no concrete evidence, it's not a stretch to assume that some users have avoided participating in and promoting the forum due to this situation.

In the end though, IMO many perceive forums like Bitcointalk as a relic of a bygone age. And unless all major social media platforms suddenly imploded, I don't think the situation is gonna change any time soon. However, if Bitcointalk upgraded it's software, supercharged it's attention towards effectively managing the community and put in effort into marketing itself, it might be able to regain it's position as the premier platform for crypto-related discussion for everyone.