This "7th reason" is indeed correct. Flash player enabled browsers with many features (mesh networking, hardware 3D, easy file system, tunable font antialiasing) which were subsequently stripped from browsers and forced into the paywalled garden.
I'm not familiar with Flash's "mesh networking" (do you mean RTFMP, which hardly anyone used?), but "hardware 3D", "easy file system" and "tunable font antialiasing" are all available in HTML -- via WebGL, the File API, and the "font-smooth" and "text-rendering" CSS properties, respectively.
