According to Susan Wiggs (How I planned your wedding), we have the British Royal Family to blame for the WIC. Pre-1981, weddings were normal. By that I mean they were not big events that took 18 months of stressful planning and a house deposit to fund. Then Prince Charles married Lady Di, half the world watched, and the fairytale wedding was born.
Eventjubilee says Charles and Diana's wedding "defined a generation and changed the wedding industry indefinitely." The feminist bride mentions that the royal family are to blame even further back than this. Queen Victoria was the first bride to wear white, and the impracticality of it made it a symbol of wealth, and so everyone wanted one.
I'm not sure how many of today's WIC brides are actually aware of this - that they are literally dreaming of a princess wedding, and one specific princess in particular. No one that I've spoken to was.
I'm leaving the point of this post to Christie O. She rightly points out that not everyone is a princess, and that dreaming of a wedding that full of pomp and circumstance is not appropriate for us mere mortals and could well end up looking slightly ridiculous. Stick with your true selves, people - or try and get Prince Harry to propose to you!