Most folks who are merely investing DCA from their income, they might ONLY be able to invest 10% or less of their income, so if a person invests 10% of his income, it would take around 10 years for him to have had put a whole year of his salary into bitcoin..
Indeed it would take over 10years and though 10% could mean a decent amount, especially when you have other investments in different fields you are taking up alongside Bitcoin investment.
However, there are always rooms to do more as, DCA doesn’t limit you to any specifics in amounts you can invest, it could be more or less, through regular or irregular periods but, you’ll just be sure to be investing when opportune.