Not on the main topic, but since OP mentioned CORS being a pain: is there a reason the browser doesn't let sites do cross-origin requests, but just without any

Not on the main topic, but since OP mentioned CORS being a pain: is there a reason the browser doesn't let sites do cross-origin requests, but just without any cookies etc.? Either through a separate API or just the default behavior in the absence of CORS headers, is there a reason for that not being a thing? I can't imagine nobody has thought of it?