I think it’s because of these 2 reasons 1. GPU’s are expensive and difficult to get in quantities that microsoft would need. 2. Given (1) I would expect micro

I think it’s because of these 2 reasons 1. GPU’s are expensive and difficult to get in quantities that microsoft would need. 2. Given (1) I would expect microsoft to use their GPU’s where where its easier to monetize or its of strategic importance(bing, M365, Azure) Building a GPT4 based cortana could be a much lower priority right now. Disclaimer: I’m a microsoft employee, the opinion is my own.