DCA strategy is not only established for the poor but could also be use by anybody irrespective of their financial status weather poor or rich, however the only difference between the poor and the rich in terms of using DCA strategy is the amount they budget on accumulation basis, for instance someone that doesn't have much money could only focus on the amount he can afford maybe accumulate using $10 on a weekly basis while the rich could budget up to $100 or more on a weekly basis, so don't have the perception that DCA strategy is only for the poor because on the contrary it can be use by anyone, and perhaps that's the method so many rich people are currently using.
I understand your point but I must tell you that DCA have a limit. You can't tell a poor man who is not living with a dollar a day to invest in bitcoin because all his mind is how to survive first in his live before thinking of any other things. So DCA approach is very good for those who are working or income earners and probably they have other needs to settle or bills to pay and they are interested to invest in bitcoin so they set time frame to buy bitcoin either daily, weekly and monthly and all depends on the income capability of the person. And according to Jay JuanGee, he prefers them to use the weekly plan.