Hooking a value works by having someone hold an enormous amount of currency in reserve, then either releasing it to bring the price down or buying it up to bring the price up, thus controlling the price of the currency and keeping it close to the "hook" price. There is no one with a big enough bitcoin stash and the interest to do this (plus these "hooking a price to" ideas always fail miserably, and Argentina is a current example), so I doubt it will ever happen.