Point of order: Batman's costume was originally created to be black and gray, but, as artistic expediency/laziness eventually set in, the comic inkers "spotted the blacks" less and less, resulting in the highlight color--blue--becoming dominant.
However, even in the Neal Adams era (and beyond), narrative captions and dialogue still described the costume as black and gray.
So, while the pure-blue look definitely has a long shadow in terms of comic art and licensed products, and has its own aesthetic value, the suit was intended from Day One to be black and gray.
Food for thought!
