I don't think "chief architect" is a title at Microsoft, and it's probably worth noting that unless you're at the partner level, your pay at Microsoft will be pretty terrible compared to the rest of the tech industry.

That said, Alex's title appears to be principal engineer at GitHub, which is roughly equivalent to principal at Amazon in both expectations and comp. I worked at AWS for just shy of six years, and I can tell you that the person who created Firecracker -- which underpins huge portions of AWS's technology -- was at the same level, and while they were promoted shortly thereafter, they didn't receive a bonus (because comp packages at that level don't include bonuses at all). So, yeah, Alex is justified in sharing these details publicly, but this is just how it works in tech. (And, frankly, all the underpinning infrastructure that supported him wasn't his work -- he might have come up with Copilot, but would he have been able to without the work of thousands of others?)