There would need to be boundaries placed on any commodity price swings - to prevent unrealistic changes to the economy occurring.
With fluctuations in pricing, it may also become desirable to haul mixed cargos. In Ventana's scenario, an ALG transport might well decide to haul a couple of hundred units of mixed sundries to Elbich in order to keep their pricing at an optimum level.
And with a shifting economy, there is one commodity that will become very valuable...information!
And if the economy is shifting over time - then some groups such as Junkers, Zoners or IC may not need dedicated routes - they would become more itinerant, forever chasing the next bargain...
Overall, the economy doesnt have to vary much in order to have an effect. Small changes over time would throw in some interest and variation. The economy should also have 'manual' tweaks thrown in by admins - in order to redirect traffic as parts of any storyline progress.