What is the status of this series of guns?
Are they being dropped or just ignored by Colt?

yes

I had an instock notification from armsunlimited a few months back for the 901

I might have to sell mine so I have been looking around to see who has them in stock and what they are going for.  A few places have had them, ranging in price from about $1775 to $2400, the past few weeks.  SWFA is showing one in stock at this time.

Colt seems to be having trouble catching up on election panic backlog. All the 901s dried up and AR-15A4s have been few and far between and disappear almost the moment they leave Colt. From what I've heard they're dumping most of their capacity into keeping up with the 6920 and its variants since those are its best seller, and other models are lagging badly as a result.

AFAIK they dropped all of the 901's variants except the CM901 for LE/MIL and LE901-16SE for civilians, but it's still being produced. Brownells had a bunch of 901 parts come in recently, although most of them sold out again.