On the Patreon platform, why not use "per creation" but instead use "monthly"?

Apparently in the Patreon platform, the creator must select monthly or one time. The two options are mutually exclusive on the platform. For a software development team, one-time payment is not very meaningful, as we will explains as below:

A very different aspect of software development from other type of creation is "maintenance". Meaning if you have 1000 features, adding 1 feature can cause bug in the existing 1000 feature. Thus, in order to add 1 feature, the effort of making sure previous 1000 feature still working, is not trivial.

Since what we primarily need is "monthly revenue", we have to put the one-time revenue on a lower priority.

Also, software development is a "full-time job". It's a bit different from "artists". As software engineers, we must be constantly focusing our brain on this software knowledge. If we just "occasionally" do the software development, then we're afraid the knowledge will soon decay and the software will be containing a lot of bugs. Many users appreciate our software is because our software is very stable. From the engineering point of view, it means we must have high-quality and strict coding and testing process. It could not have been achieved without a full-time dedicated software development team.

An interesting story to share is when I used to work in another company (that is also doing video surveillance software) many years ago, we had many customers asking us to add a lot of software features. At that time, that company didn't have very strict control of coding like what we have now (as most of software company in the world did), the software soon became very unstable. It crashed too often to a stage that the customers couldn't bear it anymore and shout out that "I don't want anything fancy at all, not anymore! I just want your software to record 24x7 without fail. I just want this single feature!!!".

Ironic, right? Achieving the simple 24x7 running, turns out to be the most difficult task at all. When I was at that company, we never had the chance achieve that goal because the problem was in the architecture and methodology. There was no way to fix the problem unless we restart the software development from the ground-up, and back then this was not an option. It's fortunately that I turned out to start-up my own company, so I'm able to develop the high quality software like what we currently have.

This is a story that tells you about the importance of "software maintenance".