You are correct, it was a badly written explanation of why they don't change gears.
All of the conventional ones use lots of power electronics to chop it up into a nice sine wave.
In general, the modern technology trend has been replacing mechanical components with electrical ones. Frequency converters have become successful, and they have no moving parts and are very efficient.
On the other hand, if this can get rid of the mechanical gear at the same time, it might be a wash.
But since Vestas and Mitsubishi wind power are combining and it seems the hydraulic technology used in that Mitsubishi prototype power plant will not see immediate use.
