I'm not entirely sure. Perhaps it is due to the younger generations (since about the early 1980's) peppering English (or Engrish ^_^) in their everyday speech. At least, that's my theory on it.

Golden Week is just one big holiday now? If I remember right, it was a week with 3 holidays in it, Emperors day, Greenery day and Children's day perhaps even May day as well. People used to take the entire week, so perhaps they just went ahead and made it a week long holiday.