Here's the big problem, as I see it. It's not the dipping overall number. But (using the DVCforLess star system), it's that the vast majority of contracts are unappealing, many of which just sit there month-after-month. Out of 1014 contracts listed, 882 have the site's lowest rating (two stars). Only 132 have a rating of three, four, or five stars. That is, what I'm noticing is that the viable inventory is shrinking, but that's mostly invisible because a bunch of unsellable...or unappealing contracts (Hey, who wants Beach Club at $163? Good news, you have your choice of multiple contracts) remain for sale month after month.
Side note: if you're selling Poly, you might want to make a deal quickly, as I'm pretty sure that when incentives and MB and 2024 direct points are announced, upper end resale on this is going to take a quick nose dive.