Quote - All I want is a nice, clean and efficient OS without a bunch of BS to mesmerize me like a tribe of indigenous people seeing shiny trinkets for the first time. If an OS has to have these things to sell then one must question the developers. Why is it a hard thing to ask for? A clean, lean, efficient simply written OS?

Well, you have Linux. You have different versions of Linux, some fast and other slow.
You have also the advantage to compile the kernel to match your hardware making it a fast and very efficient operational system.

Quote - In order to run 32 bit code (under a 64 bit operating system), you have to actually switch the processor into 32 bit mode while that process is running.

The 32 bit mode is a mode where 100% of the 32 bit applications can run on a 64 bit CPU, but you also can run a 32 code in the 64 bit mode or running under 32 bit mode you can access more than 4 GB of memory

Quote -   Windows (XP-64 and Vista 64 bit) handle this automatically, switching to the proper processor mode when switching to another process and then switching back.

This thing I have really doubts. I doubt that Vista or XP64 runs under 64 bit mode, , probably repeating the story of the past of Windows 3.1 and 32 bits, Vista64 or XP64 is only running in 32 bit mode accessing over 4 GB of memory.
In 64 bit mode is not used any more segmentation, it use a linear addressing. This destroys all the Windows structure and all the Windows code must be rewriten. I doubt very much that Micro$oft did this work, probably they patched only some parts of the 32 bit Windows making it access more than 4 GB, and of course using only 32 bit mode.
I suppose that in 2012 Windows will be really 64 bit and anot a patched 32 bit sold as it was 64 bit.
You know very well the story, a full 32 bit Windows 98 depending on DOS call of it kernel, not old 16 bit Windows calls, something even much older that this!!!, the old 8086 with only 1 MB memory.

It's the same thing with running 16 bit processes under 32 bit windows; the operating system handles all the necessary mode switches automatically.  Probably the main reason that 64 bit windows can't handle 16 bit code is probably because the added complexity it would entail isn't worth it, considering that 16 bit is about as obsolete as it gets.

Stupidity also evolves!