1. People think they can afford to buy a place at $X
2. People find a place at $X+Y and say "it'll be tough, but I love this place"
3. People find out actually owning a house costs $X+$Y+$Z and they can barely make their house payments and supporting costs
4. Eventually (after enough mortgage payments) your principal payments become large enough to take on the form of "forced savings"
I think this might work for some, but there are plenty of examples where people lose their homes because they underestimated the costs. Someone get sicks and goes on LT disability at 60% of their salary and end up missing mortgage payments.