First of, the game itself isn't that long for now. It's too early to compare it with the other games you mentioned...
What's sad is that many people now don't even remember/know, how it was back then.
You say, that it's not that long, and it's too early to compare, and I say: let's compare.
Demon Boy is in development from
18th of June 2021, when there was an
initial release. Since then there were
3 content updates (
Chapter 2 -
31st of August 2021 (2,5 months),
Chapter 3 -
1st of December 2021 (3 months),
Chapter 4 (the last one) was released on the
30th of April 2022 (5 months, though
Chapter 4 was almost
twice bigger than
Chapter 3), then there were bugfixes). And now we are waiting for the 4th update.
So
3 updates in more than
10 month +
initial release. Since then
9 months of waiting. All in all more than
19 months of development.
And what about 2 other mentioned games
Milfy City and
Dreams of Desire?
Dreams of Desire's first
initial release was in
March 2017, the
final release in
June 2018! It had
12 Episodes: initial release + 11 content updates. First
8 updates were released
every month,
2 following updates -
every 2 months, the
final release took a little more than
2 months. So it took developer Lewdlab
15 months to finish the
whole game!
Milfy City has more complicated history. It wasn't finished, still it has a huge amount of sexual content.
The
initial release was in
February 2018, Then there were
4 content updates till
November 2018 (
version 0.5). After that developer took his first pause.
5th content updates (
0.6 versions with letters b-e) appeared in
October - December 2019. Then the dev disappeared until
July 2021 to release the
6th content update (
version 0.71). And since that time he disappeared again.
So the most productive period of the development was the first one and lasted
9 months. The first delay was long - almost a
year, but the update size was huge and was equal to the size of the
3 previous content updates. So we'll summarize this 2 development periods and get
initial release + 5 content updates of different size in
21 months, which contain a huge amount of sexual content.
What conclusions can be made?
Firstly the development period of
Demon Boy is already longer than Dreams of Desire's one, during which the game was fully completed, and almost as big as Milfy City's one, while only one 0.6 Milfy City's update is as big as the whole Demon Boy game so far.
Secondly the development speed from the beginning was constantly slowing, and now there is a long pause with lame excuses. So we can state that development of Demon Boy encounters the similar development issues as
Milfy City: the first relatively productive period then delay with an attempt to release a bigger update.
Thirdly if we compare the story development we can state that
Dreams of Desire's story was fully completed,
Milfy City's paused somewhere at the middle, while
Demon Boy's story is only at the beginning with not much sexual content, and the prospect for future successful development is unfortunately very foggy.