No, that's not how it works: first you will have to pay him at least minimum wage, so there's the first bit of interference with your "freedom to exploit", then you have to figure you need a job done so you need to find at least one contractor willing to do the job, if they all turn your offer down you will have to change your offer. On the other hand the contractors need to put food on the table and are generally less paychecks away from starvation than you, the (potential) employer are, so they will have to cave in to a reasonable offer from you at some point (though unions will support him to hold out longer). In the end you will meet halfway. Employers use their larger financial reserves, threats to move abroad or import workers from abroad, expensive all-star lawyer teams, and large (per capita) political clout as weapons, while employees use unions, threats of strikes and their larger numbers (they have less political clout per capita, but they have more capitas).
If employers could set wages all on their own the median wage would be something like $200 a month and most employees would be living in the squalid conditions of 19th century Western factory workers or 21st century Indian factory workers, and that's assuming slavery would have been abolished... And oh yeah, weekends and holidays would not exist and the workweek would be something like 72 hours.