Why are we even talking about this. Mobile devices, desktops, servers, etc all have differing requirements in use and needs. By combining them, you end up with the lowest common denominator which only serves one system well while compromising the others. All of the weaknesses from different devices and none of the unique strength's from each.
MS wasn't the only one to have experimented with such simplified and "Streamlined" setups. Apple was looking into that in the early 90's. Apple did release it as part of the OS and elements of it continues to this day, but it was never made to be the source of primary interaction because of how unwieldy and restrictive it was.
If you had any awareness of history, you would know better.