Google (and others) may not have released model weights, but they've published papers, which is ultimately what makes the field advance. OpenAI not only did not publish any GPT4 paper, they haven't even said how many parameters it has.
Closest competitor DeepMind played games, which is intuitively closer to what humans do, but its relevance given aspects of deep learning is questionable.
Reinforcement Learning is part of what OpenAI is doing. I don't think Google went down the wrong path. If anything they should have run down the path they were on.
It's 99 pages of marketing material
Disclaimer - I work at Microsoft, in AI, and have no internal knowledge about gpt4.
They likely did extensive small model building on the gpt-4 architecture to establish hyperparameter scaling laws and then did a predicted build in exactly the same way chinchilla did.
Why isn’t chinchilla running google AI chat or whatever then?