They did that for a while during the GPT-3 days, Ada, Babbage and Davinci all were/are different variations of GPT-3.

Certainly, but GPT3.5 is effectively free via the API, especially considering you have to hit $5 or whatever to even be as expensive as ChatGPT (and it's even relatively difficult to rack up a high bill on GPT4 now that they have token rate limits). The problem of general and global access to unrestricted LLMs is a very, very serious question, but here it's largely a question of engineers and, since it's relatively difficult to spend more than a Netflix subscription via the API, I'm assuming this is conceivably in budget.