The econ 101 observation feels like it falls apart under light scrutiny. The market sets a rate, but which rate is more "natural?" When individuals negotiate directly with employers, they tend to be at a disadvantage. An individual has less knowledge and bargaining power than an employer in almost all cases; so can we call the rate set by these negotiations to be the "natural" rate? Conversely, when bargaining collectively, employees are able to pool knowledge and resources to bargain more effectively, and they have more leverage as a group which allows them to negotiate on a more even field to the employer. I would consider this outcome to be more "natural," and would argue that it is not that collective bargaining results in higher wages than the market would set but that individual bargaining results in wages that are artificially lower than those of the market clearing rate.