Man, I am so much more pessimistic. After reading you I feel that's what people want to believe, but it sounds so naive...
In my humble opinion, the relation between content and time in this case, is hellish. I have enough experience working on similar products (for personal use, my gf, me and some friends) to know that it doesn't take 6 months of work (how much time they took last time? Three months only? Can't remember, that wouldn't be that bad) to make a bunch of pictures, some of them not even that good, pretty generic, with just some text tied to it, nothing original or ingenuous. They are not even adding features, they don't need to do crazy stuff with the code, they are just filling the game, the framework is already done.
If at least we could say that there are no bugs at all... that they make really well polished content, but that's not the case.
Now, I am thinking in one person working full time, 8 hours a day. If you tell me that there is an entire team working on this, I would say... nothing. Nothing, just because I am paying nothing for the game. So who am I to whine about it.
However, it seems obvious to me that this is that model of doing as little as they can, to keep living thanks to the donors. As long as they keep getting money, they will make it, and they will do it as sluggish as possible.
I remember full complex games like... fairy fighting I think was named, back in the day... really fun games with a lot of content, made pretty much by one guy... and the relation of content and time was so much better. Back in the day. Before this model really took off.
It's not a scam because they are actually working on the game, and because we can still play it for free, they know what they are doing there. But from an ethic point of view, I think this is as close as it gets, sadly. There are a lot of games today that work that way: Do the minimum, try to not promise anything, bring a bone once every 3 or 6 months and keep receiving money for it.
Maybe I am wrong and they are working as hard as they can, but then my questions are different, more on the line of "do they really know what they are doing?", and I am not sure which narrative feels worse...