It's easy to invest when you don't have another means of survival; the disadvantage is that such investors may not be able to hold until the bull market is reached. While there are some people too who don't have alternative sources of income and yet are still investing for a long period of time, such people are those that are still under the care of their parents or guidance.
For example, there are some teenagers, probably at the age of 18, who are already aware of Bitcoin and any money they get from their parents, uncles, aunts, and friends they will just invest in Bitcoin and hold it for a very long time. They will not bother to sell because they don't have any responsibility yet; they are still the responsibility of their parents.
Yes, I am one of those people and even in this case I ended up selling anytime there was a medical emergency, even as recently as three days ago when mother in law was taken to Intensive Care, I had to spend 900 dollars that I didn't had, but took a loan out basically.
So all in all, sometimes the poor can't just invest, because at the end of the day we can't even survive with the income we have, and because of a few things our whole life gets crumbled, and there isn't anything I can do about it. We try, I do try to put anything I can, even if it's a dollar I will invest, even if it's 10-20 doesn't matter if I find a few cents then I would invest that, as long as I do not give up, I trust that one day I will have a good amount.