Sadly this game is split into many DLCs, at that time the devs didn't have the funds to release a full game as far as I know. I'm still hoping they will find a solution to integrate everything even for a bigger price at least it's the full game.
Can't speak for the smaller devs, resources and everything are killer...time, bills, and god only knows what steam requires besides just a developers license (everything that makes money in life is a gamble--nothings free these days), but when big companies like sqaure enix do this (hitman for example)--I hang the game up.
I can accept it from indie devs, I can accept most moves from indie devs except abandoning an early access title people pay for--thats just robbery...and one of the reasons we put off doing steam from the start (not like its any better on patreon or something--but at least they know they're supporting development not buying a full product)
I'd love to give the world the break down of how it works, but even if and when we made it there...VNs are different than action games or RTS, IMO they actually take longer to make and i've started quite a few game projects in my day. For most games, the assets are change dependent and as long as you have those (which you shouldnt start without a basic amount anyways), it really just depends on your own life finances and time unless it costs to release them on platforms, but that doesnt really explain partial releases either.
Sorry...i'm rambling because these are all realistic thoughts from a state of a dream lately...in this case i've never tried the game and I have no idea what development and release consisted of then...but generally speaking a piece by piece release doesn't make sense as being cheaper, in fact I think that would cost more with digital keys.
AWA 
