I don't follow the game's development super closely anymore, but I was in the community back when it was just starting to transition out of being a concept with levels made using well-known characters instead of originals. When the official version of the game first came out, it was mostly content releases because it would be ridiculous not to start with that. It was proof of concept for what the future development of the game would look like. It gave us real examples of how the new game would work and they were able to collect feedback. Since then, the whole thing was overhauled and tools were developed for modders, because that was one of the most active parts of the game's early supporters: the people who made new levels and the people who enjoyed playing those levels or were drawn to the game after seeing those levels.
It's not that they aren't working on anything, it's that they're actually putting the old fans first. I've seen how fast Kom can put content together, but programming takes their team more time. A lot more time. I'm sure that when all of the stuff under the hood is done, updates will start coming much faster.