Ooo thanks for the ton of info! That was very enlightening.
Yes I do agree with you that the flooding of idle game may have devolve the quality of games due to the ease of production of making one. However, I think it is lack of game design knowledge rather than programming is what cause the bad ones to multiply. There are some really good gems out there that would be trivial to program. One that I really like is Idle Factory (the same author as Idle Reactor). Think of it as Factorio as an idle game. It is also notably harder than most of the idle games out there since you have to not only manage the ratio of each materials and its product but also manage production path and routes to minimize the amount of space you need. I'd highly recommend it for spatial thinkers!