It is not everyone can raise a capital to start up the investment of bitcoin. From my own experience, many people want to start the investment of bitcoin but the amount they plan to start with is not encouraging. Some want to invest with $5 and below. If someone is investing $5 monthly, when will the person hit a reasonable amount. You can start with a good amount of $100 and above then you can top it with the $5 monthly and the discretionary spending.
A friend of mine has been very eager to invest in bitcoin since last year but unfortunately for him, he simply doesn't earn enough. Being a family man with 3 children, he's monthly pay doesn't even buy good food and welfare for them let alone, him being able to save out some money to invest in bitcoin..
So you are right, many does know and want to invest in bitcoin but unfortunately for them, they don't have the financial capability of capacity to achieve this successfully, and we cant blame them really since in most countries today, the economy isn't even helping citizens at all.
But on the other hand, I will still say that who ever have the ability to invest $5 every month, let him do it so long as he has a stable paying job or business that would allow him leave that investment there for a very long time for like up to 10 years or more, if someone can consistently invest $5 in bitcoin every month for 6 - 7 years, thats money, couple with the fact that the price of bitcoin may rise and the person will make profit from what he has previously invested.