<i>It doesn't seem that, in practice, users want to modify their computer systems in that way</i><p>Don't confuse core product with actual product.  If, before the 20th century, you had asked people if they wanted to partake in mechanical flight, they would have most certainly said no.  They couldn't distinguish a core product that would differ significantly from the current actual product of a bicycle with wire-wings.<p>Kay was right.  And there are people out there right now, on the equivalent of a crisp morning at Kittyhawk, trying, and trying, and trying to prove it.