I've been here for more than a year now. I'm hardly an oldie. But with that said, here is my rebuttal based on your hypothesis that the quality of the boards is going down.
No, it isn't. Yes, there are older members getting banned. Darth_Mobius, Jallil Vlos/Darth_Empyrean, who we knew so much about their personal lives, perhaps more than we were comfortable with. The Necroswanson, who gave at least me a new insight into Satanism, making me realize firsthand that it isn't at all just "rah, sacrifice". And most recently, Max_The_Reaper, whose posts were always caustic, but usually quite entertaining.
However, each of these users has met their tragic ends. Darth_Mobius went down for being overly confrontational and mean-spirited, his banning post linking Christians with retards. Jallil went down soon after, for an overly insulting post which, from what I hear, mixed attacks on certain users with porn. Necroswanson followed, finally taken down for his insulting and often rude posts. And most recently, Max_The_Reaper has gone down, defeated by his own hubris. That and being a jerk to everyone he disagreed with, a trait he shared, though to a lesser degree, than Darth_Mobius.
But through these bannings, others have emerged to take their place. Cheeze_Pavilon has taken up the reins as the resident facts giver, with intelligence to match his views. pimppeter is the resident reviewer with great reviews, and knowing how to entertain through text. And Neonbob, whose avatar is a common sight on topics, usually taking up topics as a snarker, his avatar of whales and explosions a common sight on topics that are started by a user of oftentimes limited perspectives.
And most importantly, the mods we all know and love are still here. Wilson, nilcypher, and the recent additions of Baby Tea, CantFakeTheFunk and UltraJoe. They are still the fair, impartial, and oftentimes quite entertaining mods we all grew up on these forums with. They haven't changed at all.
"The more things change, the more they stay the same". Never have truer words been spoken. As old hands finally fold, new deals are handed out, oftentimes just as good or better than the originals. That has not changed, and will not change in the forseeable future. As a year long veteran of this site, I respectfully remind you to look at the whole, not just the part you disagree with. For every GEMS, there is a Cheeze. Remember this, lest you make a rash decision on biases.
Edit: 2 years. My, how time flies.