Quality over Quantity. Thankfully Mods seem to be closing a lot more threads that are just utter tripe these days, Quality threads stay on first page, and crap ones leave it for good or get closed.
I should point out, in keeping with threads initial point, That there are good threads that leave the first page. But they leave due to people sayin all they have had to, and those threads often make it back to the first page when something new comes to the surface.
I've been on the forum years, and I dont think its declined much. Although yes, some of the good posters have left. Which is a shame, especially from consoles where i frequent. But thats not really whats been asked in the OP