The main thing that got bitcoin off the ground was that businesses and services took a chance on bitcoin, accepting payment with an otherwise useless currency at the time and now look where it's at.
I disagree in part. Silk Road got Bitcoin off the ground; when the feds closed Silk Road it became more commercially appealing. After the Feds took it out of the picture a very toxic element associated with the currency was removed. If that site had never existed BTC would probably be worth nothing