While I agree with some of the things you've wrote, to be honest ChuableSoft's bankruptcy wasnt unexpected at all and I dont think they fall into that category. Yeah their games were not bad, but you just cant win with making decent games, you have to sell them as well. With a "hey as long as we make okayish games we dont need to do anything else!" mind unfortunately the bankruptcy was inevitable.
First of all, They always had a very bad advertising policy and didnt put enough money to advertisement of their games at all. The biggest example of this was Ano Harewataru Sora yori Takaku's sales, their probably most succesful game in the last 6-7 years. Many people have liked it and wrote great reviews about it, Also have won a couple awards etc etc, in short it was a great game. But how about its sales? Unfortunately it was "Way less than 1/7 of Yakimochi Stream", a kinda worse than average nukigeish game which got released at the same month with Haretaka.
What I'm trying to say is, writing a "masterpiece" is not enough at all. You have to catch customers’ attention as well or some random game will just take the all delicious part with proper advertisement, specially if you released very bad 3 games in a row before the current game. Stuff like getting some popular seiyuus, making people talk about your game at the radio programs etc. would rise their sales for sure, but they didn't bother at all. Yeah going bankruptcy is kinda sad, but if chuablesoft can only take 133 points from the total 3861 September sales with their best title, maybe they did something wrong after all.
Also for some reason they always released their game at the wrong time as well. For example the SukiSuki you've talked about. Yeah it was good and enjoyable, but if you release it at the same month with Primal x Heart & Sakuuta & Koikake, it'll just get crushed, specially with their bad advertisement thing.