Women weren't really allowed to have much to do with their own fashion for eons. It was usually men who were allowed to be the designers and tailors. It was a male dominated industry. She might have gotten a little input here and there, because of her station, however, even then, a Queen still had to answer to whoever she was married to most of the time (depending on her marital status and who inherited the throne, etc). Anyway, I really don't believe that such a high neck was a woman's idea. Queen Alexandria might have been used as the icon for trend setting, but I really doubt much that she did all her own designing and sewing.
Also, upon close inspection, you can see that this was a jewelry piece, not an actual part of the dress itself.