My step-son started his own business competing with his former employer. The former employer is fully union while my step-son’s company is not. He is killing his competition, not because his employees work cheaper, but because with no union labor he can be more flexible.
His employees are paid a VERY good wage based on work completed rather than by the hour. Also, at the old union place, if they needed someone to work until 12:30, they would not do it because the union said lunch break was between 12 and 1. Even if the employer just wanted them to shift their lunch break one day by a half hour, no dice.
Sure, you can take advantage of non-union employees, but you can also get rich, and enhance your employees riches as well, when the whole organization works to better the company as a team. Unions are overtly anti-teaming, which is always a recipe for disaster in a company.