Computers are apparently not powerful enough to do that today. Go on, fire up Windows 95 in a VM and be utterly amazed at how responsive it is compared to your current Desktop and it has vastly more themeability. This is the future we have made for ourselves.
A long time ago computers were mostly used to run local, trusted, programs. Now they run remote, untrusted, code and this is considered a feature. And this remote code needs a powerful machine that's why the interface is kept to a minimum.
Enormous shame, really - there’s real value in customisation support.
Also both toolkits today are still less responsive than Win32.
I would hope so, it's running on hardware much more powerful than what it was designed for.
I don't have access to a windows machine right now, but if nothing else I'd bet there's just a lot more things trying to run at the same time, and it's not that the UI is slower, it's that the OS is doing more things.
People who say this have no idea how much more powerful computers are today. My system is currently using 9 of 32GB and the processor is running 1% of its total capacity over 6 cores. Why does it take more an an imperceptible amount of time for a new Explorer Window to appear?