Whilst this is true, in theory, in practice it tends to be the case that the real pressure on employers to provide good working conditions, high wages &c only comes when there is full or near-full employment. Businesses have the choice in such times of cutting their profitability by raising standards for the workers or of not doing so and losing their employees to those who will with the concommitant fall in profitability. The corollary is that businesses prefer that certain degree of flexibility in the workforce that results from a certain level of unemployment.