Dunno if that's a rhetorical question, but I'd wager that we have reoccuring hot topics that are usually variations on the same themes: smoking, ROFR, waitlists, who's resort is the best, long BWV halls, bus service, bugs, why don't we get discounts or more perks, pool hopping, snotty CMs, room occupancy, etc. Maybe it's easier to resurrect an old thread than to come up with a creative tweak for a new one.
And here's something else - for habitual posters, I can tell you what their replies will be on a given subject before reading them. That's not necessarily a bad thing, 'cause we are who we are.
There's nothing new under the sun, I reckon.