Actually, despite it being a dick move and seemingly dumb, destroying a market isn't. The reason many people think that in the english forums is because Americans tend to think short-term gains instead of long term. In the mid term to long term, destroying a market drives out competition, thus resulting in allowing a monopoly to reset prices back to the highly profitable levels (hence legislation to prevent that IRL). With luxury items like orchestrion rolls, the supply is only limited by drop rates, so valuation is a combination of how much someone wants an item versus how badly all the impatient sellers want to make those few extra gil.