No, definately no landing if the cabin isn't ready. Ihave had one embaressing orbit on approach to EGLL without the cabin being ready, our fault completely. But on the other hand, if the Capt has made a 10 min to landing call, he could "assume" the cabin crew will comply, but then again have they encountered a problem preventing them from completing their landing procedures? Now, our SOPs are standard lights at 10 thou plus double chime on s/belts - written on same line....., followed by cabin crew 10 mins to landing, and turning finals a last call if needed for cabin crew take your seats please. The senior will then poll his/her cabin crew for seats/belts, and then report cabin secure for landing.
I know shorter hauliers will still have service in the descent, I've always watched the mad rush on some carriers, last-minute.command, slap-click-clunk of the stowage boxes, cursory glance at seatbelts, cabin lights, safety annoucement nicely leading into heathrow express tickets along with lotto and phone cards.