"The most saleable good" in our economy is money. The majority of explicit trades for goods and services involve money. Of course, that is now and we need to explain how this happened.
If I have a good another wants then I may accept something I don't directly want as payment. Of goods I indirectly value, I should value more the goods that are most saleable as they provide the shortest path to goods I directly value. Throughout this my valuations are based on expectations of others' future valuations. We can think of the path from regular good to money like a feedback loop. It's the economic bubble that doesn't burst (except when it does and we all switch to silver or furs).
Of course it's much harder for the value of the anomalously valued good to crash in a real economy because of things like taxation (this is almost chartalism).