DCA method is actually for this type of investment, where someone from a poor or middle-class family will regularly invest a percentage (no matter how small) of their income in Bitcoin. The percentage of investment will depend on the amount of their income. However, I think that a small part of the income, such as 10%, allocated for investment will be a satisfactory percentage of investment.
In the current era, the average income of every poor family is at least $150 to $200. And the average income of every middle-class family is at least $350 to $400, in this case, if a poor family invests 10% of Bitcoin on a monthly basis in DCA, its monthly Bitcoin investment will be $15 to $20, and a middle-class family's monthly investment will be $35 to $40 as 10%. But, if a middle-class person wants to invest 20% to 30% of their money, they can easily invest $100 in DCA on a monthly basis.
Therefore, it is enough to start investing this amount as their income, they can increase the percentage of investment as their income increases in the future. And thus they will continue to slowly grow their Bitcoin investment stash, and if it continues to do so in the long term (at least 10 years), they may get something better than they expected in the future, from which they will be able to improve their financial situation a lot in the future.
What you have said is nothing far from the truth. No doubt DCA is a satisfactory method of investing in Bitcoin. It is very feasible because they can invest in small amount and gradually grow without worrying. $10 or $15 might look a bit comfortable for the middle class people to keep investing for long term. but for the poorer families even that $15, $10 or $20 could be a lot when they have taken care of their expenses, unexpected expenses or emergencies.
Ricardo, its not all about allocating a fixed percentage by the poor families or middle class , its more about their ability to commit to their investment without jeopardizing their basic needs. For the middle-class your suggestion for 20% 0r 30$ may feel too ambitious for many. And the reason is because they have very competitive priorities like education, housing and health (imagine a family of 5). 10% is more comfortable for me here. Also to the poor families with keen interest in Bitcoin, i will rather say they don't start until they have moved up financially, to them 10% might be $5 or $10 which is high for them, in some rare cases 10% comes out nothing for them.
You shouldn't forget that investing in bitcoin is based on your discretionary income and I believe that there's no way a poor man receiving $100-$150 wouldn't have discretionary income if his expenses is not more than his income, because as a poor man you need to only focus on your needs and try to save a little part of your income to achieve something better in future. That's the money that you will put into bitcoin.
If the poor man discretionary income is 5%, that's bad which is $5 out of $100 and if it's $150, $7.5 will be his discretionary income. He can still use such amount to buy bitcoin instead of him being discouraged that it's too small. If it's weekly that he gets $100, he can buy bitcoin biweekly at $10 and if it's monthly, he can buy bimonthly with $10 overtime. While he look for a means to increase his income, so that he can also increase his DCA amount, the most important thing is that he has started his bitcoin investment.