> Nope. It's to make money for the developers.
Sure.
Let's look a simple condo case: Developer pays X for property. Developer spends Y to build a building. Developer sells N units for Z. To make money, NZ has to be greater than XY aka the total value of that parcel is now higher.
> Reversed causation. It's literally just supply and demand. Places with high demand and not enough supply have growing property values. Places that are actually able to build housing to even kinda meet demand are doing much better.
Yeah, short-term, why was that parcel before the condo building worth less? Because there was less demand for what was there before than for what was there after it. Development increase short-term values by providing immediate units with nicer amenities or better condition or more size or whatever. Probably pretty uncontroversial.
But also development increases long-term values by continuing to grow long term demand. Development, residences, businesses, services - in the most successful cities, all that flow of money produces more and more demand and value over time. Not a lot of demand to live on an empty lot in the middle of nowhere where there's not a nice house and there's no nearby jobs...
So flip the causation: if there hadn't been development to allow all the people in [popular city of your choice] in the first place, it wouldn't be so popular and have such high demand today. That's not completely separate from geographical factors like rivers, but it's also got a lot to do with development - take, say, the land where a river meets a train line and compare it to the land downstream without the train.