I think this is a bad way of thinking about bitcoin and advertising it. "get rich quick with bitcoin!"
whenever I tell anybody about bitcoin, be it a friend or family or someone on the internet, I have always tried to stick to the benefits of it being used as a currency not an investment. and we need more users who adopt bitcoin as a currency in my opinion, rather than more speculators to play around with the price and make more $$$ in return when they dump and exit.
i think theres no one says "get rich quick with bitcoin " since according to the news koch bought the coin in 2009 and the news comes out at 2015 meaning it took him 6 years before tasting the goodness of his investment..and about what OPs title want to be a millionaire .mentioning no specific time,if you invested in bitcoin it will be depending when would the price grow for your target profit