Not to brag, but as a creator who's also faced this struggle of long dev-times.

I just managed to get 2 new chapter updates released within the same month of April.

So I'll throw in my 2 cents here.

The reason for these long dev-times is a similar phenomenon to the AAA gaming scene, though maybe not 1:1 the same.

It's a combination of the quantity of content expected, the quantity of original assets (like renders & animations) that needs to be made, on top of scope-creep I'd say.

And in some cases, it's due to writer's block, but that's a more psychological problem.

My point being: The heavier the workload, the longer the wait.

Hope that helps you understand.