I understand the reason, it was to simplify it. Make everything big for the blind to see, make it simple so that nothing complex can even be done on it. And it's a shame. And iOS is not a modified interface, it's a redesigned interface. I was saying to take the OS X input, and tweak it for touchscreen.
I think you're underestimating the effort required to "tweak" a desktop interface to work in a touch-first environment. I'm not certain anyone has been able to get it right yet, actually.
Apple didn't build IOS so that everything was big for "the blind to see," but for fat fingers like mine to hit touch targets without ambiguity. And they didn't make the interface simple so that "nothing complex can even be done on it," they made it simple because the dimensions of the screen and the interaction mode demanded it. Now that screens are bigger, side-by-side multitasking and picture-in-picture style interfaces begin to make sense, but can you imagine running a full-up windowed display manager on a iPad (or iPhone) sized screen?
Wait, we don't have to imagine - you mention it yourself. It's the remote desktop apps. I use them from time to time, but only for kicking off batch jobs or checking status of something or other. The experience is uniformly a pain, even on an iPad sized screen. I'm glad Apple (and Google with Android) decided on a touch-first experience.
Now, with regard to complexity of apps: there are some
tremendously complex applications available for iPad (and iPhone, for that matter). It's just that, to a greater or lesser degree, they're not nearly as
visually complex as OS X (or Windows) applications. They can't be, because they rely on fingers as the pointing device, and fingers aren't nearly as precise as mice or trackpads.
So, why not design a system that can use fingers
or pointing devices? Lots of folks on these forums seem to prefer this mode of operation, but it's less than ideal. Either you design for the lowest precision pointer - the finger - but then why do you need the mouse again? - or you design for the high-precision pointer - the mouse - but then touch targets become impossibly small. As several people on these forums have pointed out, Microsoft went with the latter solution, and compromised the tablet experience.
There'll be an opportunity to see how Apple resolves the target size conundrum as developers begin building applications for the Apple Pencil. It provides the direct interaction of touch with the precision of a mouse. We'll see how app developers use this newly developed capability.