Quite the opposite, really. Some of the long-timers are becoming purely complacent, which leads to really shitty, content-free posts, for which they are banned/suspended.
When I first got here, sure, I tended to listen to people with higher post counts, but now I've come around to realizing that a well-presented opinion is just that, no matter who the hell says it, and I'm not going to dismiss the post of someone with seniority as "they've been here so long that they assume everybody already knows their stance, therefore 'lolwut' is totally acceptable, self-contained post."