> Suppose you see an area in upward economic trajectory, you buy a bunch of land/properties, then do fuck-all for the next 30 years while the hard work of everyone around that land causes your land's value to increase. You contribute nothing, while benefitting from others' contributions.

In a market economy, if it's a known fact that the area is in an upward economic trajectory, then the future increase in usefullness of that land will already be priced into the land today. You can't just make profit (in expectation) by going and buying land in an area that the market already knows is going to become more productive. Competition amongst investors will drive expected profit to 0.

The only way that you can actually make a profit as a speculator, is by bringing new information to the market. The rest of society thinks this area has no potential, but you have good insight that is costly to figure out, which tells you that the area is going to be more productive. You take a risk and purchase the property. You are compensated for the risk and effort you undertook, and if you're wrong, you are punished by losing money.