Looks like a civil war broke out in the comments. I'm trying to summarize your all your points now and respond to them. If you still disagree afterwards, so be it.
1. "The dev is behind schedule"
This project works on a "when it's done" basis
2. "We should financially incentivize the dev to establish a schedule"
Noone likes to wait, but all updates so far have ben excellent and plentiful. Why change a working system? The dev is putting out awesome stuff right now, punishing him now would be really inconsiderate.
3. "The dev is working slowly if you do the math"
I completely disagree. If you just take playtime divided by devtime, there are surely faster devs out there. But I'd argue that these playtime hours have a lot of awesome in them. Just comparing the numbers and not the quality isn't fair.
4. "Patreon is really expensive if you sum up the total spending on the project!"
Correct. 5$ per month reaches AAA prices in one year. If you want to optimize your finances, Patreon is not for you. If you just want to pay a one time amount, you can do that! Get Patreon for a month, any amount, and cancel in time. The dev guaranteed that Eternum will be free forever.
5. "Why are there no dev updates here?"
Dev updates are on Patreon, Subscribestar and Discord. Dev updates on Itch would annoy those who just want release notifications.
The dev could put the progress banner on his project page. By not doing it, he encourages people to get deeper into the community and I don't blame him. Just click on the Subscribestar banner an there it is.
6. "The dev doesn't care about his fans, otherwise he'd communicate more!"
Actually, he is quite active in the comments. And he's active on the aforementioned platforms as well.