Until very recently computing has all been utilising the benefits of this year's more powerful and more resource hungry x86 processor. Relatively cheap laptops are more powerful than supercomputers 15 years ago but the user experience is not particularly more responsive because software gets increasingly bloated.
ARM devices are really a different proposition, on the plus side they have no moving parts and a long battery life, however they are a very different architecture to x86, and making the OS perform well requires lots of differences. Linux (and therefore android too) was always built to be a modular system and one thing it does well is support different platforms with many compatible but swappable components at every level. The world's top supercomputers and the £25 Raspberry Pi both happily run Linux.
Windows is very different. It is a set of very tightly integrated libraries, which has its benefits, but they all need to be scaled down to work on ARM, you cannot just swap out some resource hungry component for some open source project because the system is so interdependent. Scaling down software is much harder than scaling it up.
Therefore I am not suprised that Samsung found Windows' ARM version slow and resource hungry. Just because Windows dominated the x86 era, it does not mean it will be suitable for the new and disruptive ARM age.