at that time there was no competition , also no one was interested that much in crypto currency and blockchain technology , so price was in cent and also bcoz of monopoly bitcoin has all the room to grow individually and dominate entire market for few years . still it is dominating 40% market just bcoz of its early start .
regarding price of bitcoin in cents and then growing to 20k dollar , then you must also think about its supply and reward per block which is halved every 4 years . supply is very less which makes it high priced coin .