Yes both the same model "GPT4TurboChat", the only difference is on the WebUI, there is a hidden System prompt in front and they it also has set parameters, TopP, Temp and co which you are not able to change.
So the output is not exactly the same but close.
but the base model of GPT3.5 and 4 was never open for anyone outside of openAI.
What gives you that expression, looks like completely the opposite. Now only Ilya left on the board, Greg Brockman quit too. It looks more and more like a normal corporate board.
No the opposite, only Ilya Sutskever is left from the founders on the board since Greg Brockman quit too. It will be more closed up and profit oriented to keep AI "safe".
there are other finetunes but not from 01.AI yet. Now you have more options