By joining Microsoft, they retain access to all the data, weights, and infrastructure they had at OpenAI. They don't have to start from scratch and ramp up. They can start up right where they left off.
Wouldn’t surprise me if Sam and Greg are back on the startup path by week end.
This just seems like PR to give MS a way to paper things over after such an abrupt firing.
Remember, Microsoft has an exclusive license to all models that come out of OpenAI until they reach the pre-agreed income threshold, which given the current trajectory of OpenAI, will not happen anytime soon.
I guess at least it gives them access to the OpenAI models to use internally, which they kinda need as their ways of working (Greg especially) will be highly dependent on having them now.