No they are adding zero value, they are riding off the corrupt system and taking labour from others.
Also in most casts they are not putting capital in, they are borrowing from a bank who create the debt. They are little more than outsourced debt collectors.
Yes but my main point is that the primary gain was on the land due to govt policy. These people are typically amateurs who basically paint a wall. Unskilled labour plus a few $K in materials == not much. Yet the gains are significant.
If you put your own capital and work into something, and its value increases... that's what an investment is.