Why are costs normally higher for MNCs (Multi-National Corporations) than for purely domestic firms?

Please explain MORE informations about one of each reasons ...?

reason 1.Monitoring managers of distant subsidiaries in foreign countries is more difficult.

reason 2.Foreign subsidiary managers raised in different cultures may not follow uniform goals.

reason 3.Sheer size of larger MNCs can create large agency problems.

reason 4.Some non-U.S. managers tend to downplay the short-term effects of decisions.