If that is the case, yes. Basically you are saying that, because of a quirk in human psychology, the only way to get people to donate, over the long term, a portion of their income, derived from them doing jobs they are much more productive at than building houses, to building houses, is to engage them by having them build a house themselves first.
The question then becomes, does this actually happen? Do people who volunteer to build homes end up becoming lifetime donors? Or are those two separate sets of people?