Why do you think non-HR managers are becoming more involved and what do you see as the main benefits for more involvement in HR from managers and supervisors?

Traditionally, human resource management practices were developed and administered by the organization’s human resource department. Line managers/supervisors are now playing a major role in developing and implementing HRM practices. Why do you think non-HR managers are becoming more involved and what do you see as the main benefits for more involvement in HR from managers and supervisors?