I think if you were paying attention at the time, CoT and ReAct loops were already "well known". Lots of GPT wrappers at the time were doing it, I remember doing CoT to help measure the calories for a recipe. The problem is tokens then were quite expensive and doing experimentation on it was pretty expensive for an individual. I once accidentally spent $20 trying to categorize a Who's Hiring post from here lol.

It was a short-lived time though. I think only a few months before Deepseek really RLed the reasoning which produced much better reasoning than just prompting a CoT out of the model.