....
The best transcribers could transcribe without being able to read or write (i.e. interpret what they see) .....
I disagree.
I have transcribed many family history documents that are handwritten. I have done so for decades. If I was not able to read and write, I would not be able to transcribe.
Most of these documents that I have transcribed are in the style of longhand that I was taught at primary school. It was taught in schools throughout the western division of NSW at least from the commencement of compulsory education (1870s in the far western townships).
It is a style that is no longer taught (ceased in the early 1960s). Most of these documents involve names of central western New South Wales localities, and yes, unless you had a working knowledge of those names (past and present) you would likely not succeed in your transcription.
As an aside, here's a thread from the Australia Board re a flawed transcription.
http://www.rootschat.com/forum/index.php?topic=715385.msg5593782#msg5593782 The locality in my posts on that thread is in the Sydney region, and it is Neutral Harbour. I clearly read it as such, not just because I can read and write using that style of script, but also because I have local knowledge of the geography.
The transcriber has made a mishmash .... the index has it as Newtral.
Cheers, JM