No he isn't?? He gives rough estimates on when he thinks the update would be ready and obviously issues can come up during the creation process that can delay them.
I only support him with the big bucks when there is a release, so this doesn't affect me and I am calm about it.
Now, to give an ETA is tricky, you are more likely to fail if it is more precise, but the fact that it was a "rough" estimate makes it easier to meet the deadline. This is the case.
Extraordinary events can happen too, but he hasn't said that happened, and in any commercial relation that is not assumed, that is declared.
And this isn't the first time this happens either.
By the way, if the update was delivered 31st of this month, that doesn't mean he is bad at meeting deadlines, as that is "by the end of the month", just like it was declared.
Again, I am not mad at him, I will support him because he is talented and has integrity (by the fact that he is giving this update to the $20 patreons of December).
But I am not going to say he doesn't have a hard time organizing dates and meeting deadlines, that's all.
So... I really don't get your point here.