I wouldn't say Altman is "reneging" on anything since MSFT is a 49% owner of OpenAI and pretty much everything that transpired following the coup was orchestrated or influenced by MSFT.
In any case, since MSFT's deal with OpenAI gives it full access to source code, algorithms, and model training parameters, nothing has really changed. If anything, MSFT has gained power and influence in the generative AI space. The real losers are the non-MSFT investors and, potentially, the employees who were counting on unloading some of their shares in the upcoming private placement.