DC is adding newly digitized stuff each week. Usually around 6-10 comics each week.
It's just that they have such a large backlog of stuff, and tend to focus on a few characters or titles until a run is completed, so it seems like it's taking forever. Especially if you're not interested in the currently WIP comics. Right now, Spectre is one of the focuses, with multiple comics each week for him being digitized until they're done.
Note: This week, they added-
Blackhawk (1988) #1
Batman #191
Super Friends #25
The Phantom Stranger (1969) #9
The Spectre (1987) #25
The Spectre (1967) #5
The Witching Hour #8