It's been well documented by now that the number of parameters does not necessarily translate to a better model. My guess is that OpenAI has learned a thing or two from the endless papers published daily that your "instance" of the model is not what it seems. They likely have a workflow that picks the best model suitable for your prompt. Some people may get a 13B permutation because it is "good enough" to produce a common answer to a common prompt. Why waste precious compute resources on a prompt that is common? Would it not be feasible to collect the data of the top worldwide prompts and produce a small model that can answer those? Why would OpenAI spend precious compute time on the typical user's "write a short story of...".

I would guesstimate that the great majority of prompts are trash. People playing with a toy and amusing themselves. The platform sends those to the trash models.

For the other tiny percentage that produces a prompt the size of a paragraph, using the techniques published by OpenAI themselves, they likely get the higher tier models. This is also why I believe many are recently complaining about the quality of the outputs. When your chat history is filled with "have waifu pretend to be my girlfriend" then whatever memory the model is maintaining will be poisoned by the quality of your past prompts.

Garbage in, garbage out. I am certain that the #1 priority for OpenAI/Microsoft is lowering the cost of each prompt while satisfying the majority.

The majority is not in HN.