You do realize how much time it even takes to write a novel? and then add that it needs to have art, revision coding (even if Ren'Py is quite simple) bughunt and more?Game rework will (if they will finish it at some point - life happens) add some minimal new content but majority is drawing back again old scenes because they will scrap them.
Second game (TD) is very early phase of planning and even if they will finish SD newest rework in next year you will need to wait few years more for second game. At this point this is scam and one can argue it is so for last 4 years or more.
A novel or a draft of it can quite easily take years if you want to make something of quality.