But then how could like 50 million people or more in the u.s. alone have known about it much earlier on if word of mouth advertising just doesnt cut it?
I don't understand the question. Why did 50 million people or more in the U.S. alone need to know about it? Those that are interested in technology will pay attention to what's going on. Those that aren't interested, won't.
It takes time for a population to learn about a new thing. It always has. It always will.
A person always gains more if he gets into something from the start.
Many were scared of BTC or skeptical about it, yet here we are, and it's a good thing.