If you restart several times in succession after an update (e.g. if the machine is stuck in a boot loop), Windows automatically rolls back the update. If the machine boots but you still want to rollback manually, the option is available for a period of time after the update is installed in Settings under Windows Update > Advanced options > Recovery. It's true that once the period of time is up (something like 10 days), you can't rollback any more, but I think your statement about Windows is untrue enough to warrant a correction. Rollback of Windows OS updates is there and it works. I have relied on this functionality in actual real life practice.