The ability to use Windows in principle was likened to being able to also use a raw Turing machine; i.e. that it could have worked but would have been completely inappropriate.
I think that Unix-alikes are going to dominate any sort of high-performance computing; and I think it's more than just the network effects of the current user base. The scriptability and composability that permeates Unix-alikes is essential for automating tasks across thousands of nodes. That's not to say that it's impossible in Windows, but it's not as much in Windows' culture. Being able to ssh to any node, occasionally draw graphics remotely, all these things are hugely important. The main advantage of Windows, point-and-click administration and lots of existing software, are not advantages when you can't point-and-click thousands of machines and you have to write all your software anyway.
I think that Unix-alikes are going to dominate any sort of high-performance computing; and I think it's more than just the network effects of the current user base. The scriptability and composability that permeates Unix-alikes is essential for automating tasks across thousands of nodes. That's not to say that it's impossible in Windows, but it's not as much in Windows' culture. Being able to ssh to any node, occasionally draw graphics remotely, all these things are hugely important. The main advantage of Windows, point-and-click administration and lots of existing software, are not advantages when you can't point-and-click thousands of machines and you have to write all your software anyway.