Employees naturally jump from one company to another, and they know the secret sauce.

The difference is in the dataset mostly and to extract this dataset, competitors use a process called distillation (= extract data through actual queries) from the other models.

This yield to "funny" cases as well, like Gemini who claims "I am ChatGPT" occasionally, or ChatGPT calling itself Claude, etc.

https://note.com/maudi/n/n821a6308437b?hl=en

They all copy on each other.