2. Commercialization of Space
Space exploration is often seen as an expensive adventure, with little return to the economy, or the investor. I would argue that the Apollo program accelerated the development of miniaturization technologies, including the microprocessor - now responsible for multi-billion dollar industries.
However, it's important for investors to see tangible, rapid and direct returns on their investments. Thus, one critical component to accelerating the construction of an interstellar mission will be the commercialization of space.
John Lewis, in his book "Mining the Sky," estimates that one of the closest asteroids to the Earth holds a mineral wealth upward of $15 trillion. To put this in perspective, this is about the same as the entire annual GDP of the United States.
When you keep in mind that there are millions of such asteroids within our solar system alone, one can quickly see how space mining could very quickly become a terrific commercial opportunity. Currently, the Return on Investment for any space mining enterprise would be very low (likely not profitable at all) due to launch costs mentioned earlier. However, if the disruptive technologies currently being explored are shown to be realistic, then the commercialization of space could begin in earnest.