This may be an overly simplistic view of how the economy and economic expansion works, but it's not too far off: any economic system works only so far as the people who use it buy into it (no pun intended but, as always, appreciated), and this is true of whatever the system is. It might be the fiat system that we have all come to know and love/hate. Barter works the same, which is probably the truest form of trade there is. Even crypto works the same: Bitcoin is only worth what it is worth because crypto enthusiasts are willing to purchase it at that price. It's all really quite delicate.