GMAT Critical Reasoning (CR) | Re: Many non-profit companies pay their employees a wage significantly low

Did not understand the ans given... Can anyone please explain why C has to be the ans? Does the option mean that if working in non profit industry gives an employee a valuable work experience, then the employees should not stay in the company for long. As the work experience has high value in market, so the employees should have moved to profit making organizations in less than 5 years and thus weakening the argument?