[JumpCrisscross]

> The problem is that theses models have a predictive power approximatly the same that Aristotle Law of free fall

Having done exercises of rolling carts down inclines and comparing the measured velocity to predicted velocity, and having taken supply schedules and use those to predict price variation, I can say one set of calculations was more accurate than the other. (No doubt this was due to data quality.) Simple regressions of supply and demand curves have uncanny predictive power.

They are not a terrible representation of reality in the same way that rigid bodies are not a terrible representation. They are a limited representation that naturally extends itself. Don't confuse modern macroeconomic models with the terrifically-successful microeconomics early econ tends to focus on.

[littlestymaar]

> and having taken supply schedules and use those to predict price variation, […] Simple regressions of supply and demand curves have uncanny predictive power.

Do you have access to the actual data you worked with ? I personally attempted to study real world data to get an idea of the actual elasticity of basic products (gas, real estate, tobacco) and I've never found a single relevant measurement. I'd be really interested to see a real life example of this phenomenon.

[JumpCrisscross]

> gas, real estate, tobacco

Gas is refined, real estate is inscrutable and tobacco highly regulated. That makes them hard. (I don't think we have any good models for real estate.) Try thermal coal or crude oil or pork. The EIA, U.S. DoE and CME have loads of data.