Comment by surrTurr

my guess is that openai/anthropic employees work on macOS and mostly vibe code these new applications (be it Atlas browser or now Codex Desktop); i wouldn't be surprised if Codex Desktop was built in a month or less;

linux / windows requires extra testing as well as some adjustments to the software stack (e.g. liquid glass only works on mac); to get the thing out the door ASAP, they release macos first.