Ten (or even five) years ago, I would have wholeheartedly agreed that our current economic system is entirely voluntary compared to feudalism.
But as of late, looking at the debt you have to go into to get into a qualified profession, the fact that that the majority of people will not own land for the majority of their lives (or at least until they pay off their mortgage), the fact that an unexpected health crisis could throw you into bankruptcy or homelessness, and that medical insurance can be tied to employment, that there are no public places you could occupy if you do not have a home, that you cannot participate in society (at least in the US) unless you own a motor vehicle, that you cannot effectively trade unless you are participating in the banking system (credit cards) and that your income stream can be terminated with very little notice or reason (at least in the US), I wonder whether the choice of participation is an illusion. Perhaps not too different if someone from feudal times argued that a person can always choose to go live in the woods.