Am not sure of qwhat you meant by being satisfied, nor do I think other investors who consider the future would use such word. I am very sure that no one is ever satisfied with making more money (even the world's richest people), so why should we be satisfied with making investments?. The continuous use of the DCA strategy for at least four years, before doing whatever you want to do with it doesn't mean someone is satisfied. There might just be a very important project that has been sidelined, with the intention of making use of the investment after at least four years.
In another sense, if your portfolio happens to be very high, but you keep getting extra personal funds, then you should continue to invest. Or do you prefer to waste your extra funds just because you feel your accumulation portfolio is satisfactory enough?.
Yea, the word
"satisfy" depends on the individual bitcoin target that he feels is enough for him to acquire based on his own discretionary income in which he is using to buy bitcoin. However, I feel that anyone using DCA strategy to by bitcoin for as low as $10 might not get to the extend that he will say that he has enough Bitcoin until maybe 30yrs-40yrs time.
If it is based on present market condition, you are very correct because $10 DCA will rarely yield anything significant but that does not mean that a low income earner cannot take that path rather than doing nothing or waiting to have big amount of money before investing in Bitcoin. As long as $10 investment can be made regularly without any challenge that might force the investor to sell his coins, I think it is a good choice for a start while the investor work more on scaling this by seeking additional sources of income.
So considering the word satisfy, it depends on how old that you are and for how long will you continue building your bitcoin portfolio with the amount that you are using to DCA regularly based on your discretionary income. A rich guy who is ready to invest in bitcoin using DCA regularly without missing will have a high chance of reaching his bitcoin target because he has all the resources he needs around him to make it happen fast compare to someone that is an average earner.
This still bring us back to what you said which is individual targets and personal ambition. Age is a factor like you said and I also think that country of residence is an important factor. Someone living in the UK might have different Bitcoin target from someone living in Bangladesh or a country like Niger Republic the reason being that $10 might mean something very big for someone living in Niger Republic or Bangladesh whereas the same amount can barely afford a breakfast for someone in the UK and also less than the average pay per hour some someone in the same country. In other words, the ease of making $1,000 dollar in the UK is far less than that in a country like Nigeria where $1,000 is like dream amount of an average young person. Under this condition, someone in the UK might set a target of accumulating 1BTC in two years whereas someone in Nigeria might work for the rest of his life without being able to save 1BTC. So setting Bitcoin goals for both scenarios will be totally different.