My argument is we have at-will employment which means you are free to work at any company willing to hire you, and free to leave and join elsewhere if you find

My argument is we have at-will employment which means you are free to work at any company willing to hire you, and free to leave and join elsewhere if you find a better place. I certainly benefited myself from at-will employment and free labour market. Do you have a reason to believe the labor market is not free? Like do tech workers in NYT experience slavery/involuntary labor or industry gatekeeping of some sort?