They do this because people like to have predictability. A new model may behave quite differently on something that’s important for a use case.

Also, there are a lot of cases where very small models are just fine and others where they are not. It would always make sense to have the smallest highest performing models available.

I have *no idea* why you're being downvoted on this.

If I want to take advantage of a new model, I must validate that the structured queries I've made to the older models still work on the new models.

The last time I did a validation and update. Their Responses. Had. Changed.

API users need dependability, which means they need older models to keep being usable.