Yeah I use the term "wage-slave" from time to time, but in actuality nobody is a slave to their employer. Financial incentive for employees to stick around and be at least somewhat loyal is the whole point of paying more than a temp/contractor. The flip side of that is consultants. Employees are more valuable for long term work, even if there are some slow periods. Depends on the company's needs.
Personally I currently value the stability of being an employee. I value stability over lucrative but unpredictable of consultant or contractor. That is primarily a function of debt though. My debt is all student loans and can only exist because government has a monopoly on the use of violence and uses that violence to manipulate the free market. Schools jack prices up because the banks will lend any amount because they have no risk on student loans because government backs it all if the borrower dies and won't allow discharge in bankruptcy. Ironically I predict I will be a victim of being significantly and permanently injured by someone else, and never receive a penny because bankruptcy... i.e. Because government. Over a relatively minor sum of money.
In any event, government has figured out how to own another person. It's not to own them entirely as a 100% slave, that is not cost effective and can never work without being subsidized heavily. The U.S. government figured that out fairly quickly. The way to make it work is to give the slave enough freedom to choose to produce what they desire, to have some choices for how to live their life. Just take a real bit slice off the top. That works well, but it works even better when you take a large slice (income tax) and many smaller slices (property tax, sales tax, gas tax, marriage tax, road tax, social security tax, payroll tax, medicare tax, phone tax, unemployment tax, tobacco tax, alcohol tax, airline tax, fishing tax, hunting tax, etc...). If the slices are small enough and enough choices are allowed you might even be able to take over 70% of a persons income, productive effort, or labor... Over 70% slavery, and they won't even know it!