I believe that as long as flights are coming in, DME will get you to the resort(s)...It used to be that, after a certain hour, BAGS, Inc. would not retrieve your luggage and take it to the resort, but that time has long passed and Bags, Inc. is no longer affliiated with Disney/DME.

From another site:
Does Magical Express have specific hours?The Magical Express buses run 24 hours a day. Whatever time you arrive at MCO, there will be a bus to take you to your hotel. This applies to flights that are running on time and to those that arrive late due to weather or other delays.
While the bus service runs all day, the luggage delivery service does not. If your flight arrives before 5:00 a.m. or after 10:00 p.m., because it was scheduled to do so or because of a delay, then you must collect your luggage from the carousel on your own and bring them with you to the Magical Express check-in desk.