Now, what's wrong with this picture? Well, everything. The point he's trying to make by using The Jazz Singer is, I guess, that before that particular film there wasn't any sound on films and after it, there was always sound. Neither of these claims, though, are correct. There was sound before The Jazz Singer and there were silent films after it, some very successful and famous.
In the article he also says that "[The Adventures of Robin Hood] blazed a trail for the following year's Gone With the Wind and The Wizard of Oz by bringing the gorgeous Technicolor palette of the previous year's animated Snow White and the Seven Dwarfs into a movie starring real human beings."
The question that begs to be answered, then, is, whatever happened to Becky Sharp (1935). It's not a classic as Robin Hood, but it was made three years before Robin Hood, in full Technicolor glory and it has real human beings. It was directed by Rouben Mamoulian, one of cinema's greatest visual poets (he took over the direction when Lowell Sherman died), and to my eyes it's the better film. And yet there's not the slightest mentioning of Becky Sharp in the article. Has Harris never heard of it? That seems a bit odd considering he's writing a piece on colour cinema and its beginnings. Does he not like it? But that is of no importance here. Or is it that he wanted to write a piece on The Adventures of Robin Hood and in order to strengthen his argument he conveniently neglected to mention Becky Sharp. Whatever the reason, it's a bad one.
And it's not like Becky Sharp was alone until Robin Hood came along. There was for example The Garden of Allah (1936), A Star is Born (1937) and Nothing Sacred (1937), other great looking Technicolor films. Good as The Adventures of Robin Hood is, it's not because it broke new ground in colour film history. That article is the very essence of bad film writing, of which there's plenty.