There is no coercion in the importation of the potato and corn crops from South America into Europe. If the government gets involved in dictating we should all eat 50% potatoes (or drives a financial system that inflicts a bias towards new and risky productions -- which amounts to the same thing) that is a different issue altogether.
I'm curious if you don't really see the distinction between my and your examples. Governmental diktat in case of potatoes vs corn would mean that we should actually eat 100% potatoes (or 100% pop-corn). The same outcome would be if there is no governmental coercion as to what to eat but the majority (i.e. those who, according to you, "bet correctly" but in fact just make up this majority) still decide that
everyone should eat only potatoes (or pop-corn). There is a difference in the ways but not in the result ("ein reich ein volk ein führer"). That's the point I'm trying to make...
As you can see, there is no room for voluntarism in both of these cases
I may have used a bad example (I was in a hurry,) but my whole point is that money should be treated as just another commodity whose value fluctuates according to supply and demand. It may be a 'special' commodity in that its value depends on how much you perceive other people want it. This does increase the uncertainty as to its value, but this is no different from any other financial assets, like stocks, bonds, and real estate. It doesn't justify state control.
You may have hit upon what some say is money's 'natural monopoly' by your 'voluntarism' argument. I beg to differ, since both gold and silver having good monetary properties have enabled them to serve peacefully side by side as money (until state intervention created a lot of instability and misery when Britain pushed all major countries to gold in the mid-to-late 19th century -- for the benefit of its own elites, really -- this was the root cause of WJ Bryan's cry of 'crucifying mankind on a cross of gold' during the 1896 election.)
There are tendencies to consolidate monies (the 'network effect' as mentioned above) and this creates uncertainty for some time. But the best way to deal with this unfortunate side effect is for people to diversify carefully and not bet more than they can afford to lose. The worst way is to have the elites take control -- that's how you crucify mankind on a cross.