So now we have "Windows" isn't "Windows" argument? Look, Microsoft has kept the basic features of "windows" including how the user interface operates all the way though from 3.1.1. They have brought along a lot of baggage in the process. People, users, administrators expect that the next version will work much like the current one. I remember the jump to NT, what a mess. But Microsoft had no choice but to break a lot of expected behavior though the years, many times for security reasons, but they bring a lot of the baggage along and are forced into compromises in security in the effort to keep their user base. They couldn't just make the changes they needed to, or a lot of folks would have bailed to Linux, which had the security, and wasn't in need of change.
Yes, "Windows XP" wasn't the next version of the "Windows ME" codebase and doesn't have it.
Similar UI != same code base
React OS != Windows XP
Server OS != Desktop OS
Server use cases and audience != Desktop use cases and audience
Compare CentOS with Windows Server.
If you want a further locked down machine and featureless default install, there's Windows Server Core.
Compare Ubuntu(not Ubuntu Server) with Windows 8.