I don't think 41 days of gameplay can be considered tiny bit of content, but of course if you buy every update then this will end up being very expensive. The last update will always be a little expensive, but earlier updates are still available for a reasonable prize.
Viewing post in The Higher Society, Illustrated v.0.19 comments
I do agree that 7$ per update is rather stiff.
You may want to release it for like 1$ is you plan to have like 20 or 30 more updates before it ends.
Not to mention that having the list of owned games grow with each versions, is going to become old real fast for most people :)
You could simply decide on a total price, and simply update it normally after, like most are done. I don't think Itch is really suitable for that paid per release format, from the users' side, it's going to be both very expansive, and annoying as the version numbers are just going to pile up in our libraries.