^Developers make a pretty profit. That is their own.
Developers also face significant financial risk. Not every project is a winner. Some break even. On some they lose money (theirs, or more likely, other investors' money).
Remember too, developers are only a conduit for risk-adverse owners. 40 owners want condos in a specific new building, but the developer is the person that takes all the risk to first propose it, then build it for these 40 people. Even when a developer has 100% pre-sales (say Janion, for example), he still faces risk along the way.