Plenty of people did this in the US (and I assume other countries) during the Great Housing Debacle of the early 2000's, it's called "flipping." The problem is

Plenty of people did this in the US (and I assume other countries) during the Great Housing Debacle of the early 2000's, it's called "flipping." The problem is when the music stops, and nobody wants to buy houses, you are stuck with it, and either need to default on the mortgage or suck it up and live there.