An OS is not like a phone, an iPhone 16 will always be an iPhone 16, but the OS will change. If they used 25 you would have ~9 months the following year where the OS is a number behind, which is worse than having it be ahead for 3 months.Honestly if they are updating it based on year then I think it should be 25. When we look back it could be confusing which OS came out at which time. For example iOS 26 actually came out in ‘25. If they are looking to update the numbering to alleviate confusion I don’t think this quite fixes it.