As the founder of NLP Cloud (https://nlpcloud.com https://nlpcloud.com) I can only guess how costly it must be for OpenAI to maintain several versions of GPT-4

As the founder of NLP Cloud (https://nlpcloud.com https://nlpcloud.com) I can only guess how costly it must be for OpenAI to maintain several versions of GPT-4 in parallel. I think that the main reason why they don't provide you with a way to pin a specific model version is because of the huge GPU costs involved. There might also be this "alignment" thing that makes them delete a model because they realize that it has specific capacities that they don't want people to use anymore. On NLP Cloud we're doing our best to make sure that once a model is released it is "pinned" so our users can be sure that they won't face any regression in the future. But again it costs money so profitability can be challenging.