Parmandur
Book-Friend
Well, I noticed. I've been keeping an eye on it for weeks -- I regularly check both DMs Guild and DriveThruRPG -- with increasing puzzlement.
I can't imagine they've shut down the program, given that Rime of the Frost Maiden is basically a big DMs Guild Adepts team-up adventure. Especially with WotC being given the mandate to produce more products, a pipeline for good, reliable creators seems worth maintaining.
It could be that the DMsGuild has outgrown the program, and WotC doesn't need to proactively develop talent. Many of the Candlekeep writers are published on the DMsGuild or DriveThruRPG without being Adepts.