You're assuming the social contract follows the conventions of legal contracts between parties. It doesn't. Attempting to shoehorn it into that mode doesn't work, neither does argument by assertion.
while I do pay taxes, I never agreed to it.
And if I were to enter into a business relationship with an entity because there was literally no other choice (an email service provider as counterparty, a local monopoly, a services provider selected by my employer), then what? Willing or otherwise, you've agreed to the terms, which don't include "whistle while you pay".
Note that the State has also not consciously elected to support your ungrateful ass from the age of 0 to 18, prior to your age of majority, nor since. It simply does. That's its end of the bargain.
without the use of government coercion
I don't accept this limitation as it inherently ignores the fact that money is power, including political power, as well as the fact that all legal property is in fact a product of government coercion (as opposed to property by right of possession, might, moral suasion, tradition, or other constructs, which have their own origins).
Oh, and "property rights" aren't all that old a thing: https://books.google.com/ngrams/graph?content=property+right...
Please provide examples of the people or organizations able to arbitrage consistently, over time
Any holder of more productive land or assets (the substance of David Ricardo's lament in his Law of Rent), extractive oil producers, patent trolls, any party who writes or influences legislation to their advantage (as noted and strongly criticised by Adam Smith), market manipulators, technology and software vendors with positive returns to scale and lock-in effects (AT&T, IBM, Xerox, Microsoft, Google, Facebook) ... It's a long list, really. I'm not claiming that the power is unlimited or extends for all time, but while it persists it can be exceptionally difficult to dislodge.
The point is that initial leverage tends to multiply.