The circulation... Those who are new are bewildered with the quality and the fluidity of the animations, strong retro vibes and decent quality gameplay for a work in progress... Few months, or even a year passes, those people understand that this is a scam, they stop supporting... BUT, new ones are always being exposed to this work and start the process from over, basically a process of meat grinding where people come with hopes, support if they can, lose hope and stop supporting, all the while the process benefits the dev financially with little to no effort, and the amount of people on the internet is close to virtually endless with more active every day, the developer has tapped a remarkably stable source of potential supporters. These minor updates are vital to make the game seem active and keep the interest level at just the right level so people will find themselves in this loop. Fewer updates, the balance of supporters would fall, more updates, expectations rise and the number of supporters rise TEMPORARILY followed by a striking reduction due to the inability to maintain the momentum...
Although we all share a common distasteful sentiment regarding this type of practice in subscription based supporting mechanism, you have to understand the devs are doing nothing but a reaction to the global trend... I personally despise this malpractice of client milking, but I also understand it. Think about it for a second, if the dev had fulfilled the promise and completed the game, say, last year, that would have meant the support would cease... Why would they purposefully stop a perfectly good source of financial income for themselves (especially during these times). Sure they can just go for released versions and sell the game legitimately, but 20k USD a month is there right now, why bother losing it? You can always release and sell it, it is not like the project is going anywhere...
Part of the problem is us, we are not determined enough to impose certain principles on the developers to motivate them into showing and following more promise. Again, I hate it, but I also understand it... Sadly...