You joined Bitcointalk in late 2017, and you think the current state is worse? Bruh. If you think threads right now are rubbish, what more in late 2017? I'd say Bitcointalk's current state is great compared to the past as a lot of people stopped due to the merit system and a lot of people capitulated due to bitcoin's drop in price.
Merit system is a proof that the quality of this forum have improved, how? I am not sure but as I have observed, topics are multiplying faster than before because users are wanting merit from other users in this forum, everytime a "subject matter" is having potential to be discussed in this forum, topics would immediately rain down, and IN MY OPINION, this makes this forum, more interactive. Also, when it comes to the moderators, they are more active on deleting and moving irrelevant topics, then properly segregating them to their 'proper' places in this forum.