On second thought I think you are right. Even without the progress graph, you can still see when the game is released.I don't think so, but if this developer thought so, it's not a good strategy at all.
We know that people don't purchase paid information every month until the release date of a particular movie.
I'm sure there are Patrons who only subscribe in the month an update is released, but I don't think that has anything to do with the progress graph.
They don't have to buy oil to fill the gauge, they just have to wait and see if the dates promised by the developer are met.
This forum will be quieter and I think this developer wants that.
And that will hurt the developer's income in the long run.
But I why do you think the forum will be quieter? Paid information always leaks as well, just like the teasers.