Really don't understand why Patreon doesn't have some sort of achievements-system, where a creator would get only a % (or nothing) of the subscriptions monthly. Rest would be reserved for achievements, and would only be paid if obligations are met (for example monthly or bimonthly releases). It would reward the hardworking creators and limit the jerk-offs. If releases are thin (just to meet deadlines) the creator will be exposed meaning less patreons.
That sort of structure already exists.
Creators can choose to get paid per update or per month.
The problem is that it's not very clear how much you are going to get paid with the pay per update model, since your supporters can set an individual limit to how much they are willing to pay per month.
So if you suddenly decides to release 2 updates per month, some of your subscribers might not actually pay for it due to hitting that limit.
Similarly, a creator might update every 2nd month, but due to the increased support is able to do monthly updates instead. This means that their supporters suddenly gets charged twice as much as they used to, which might make them lower their subscription or unsubscribe entirely.
In short. The pay per update method strongly encourages creators to create 1 update per month, at which point simply switching to a monthly plan becomes less of a hassle.