Why do large corporations need many employees on many different levels to function properly?

Answer:

Large corporations need many employees on many different levels to function properly to share work load.

Explanation:

Large corporations hire people with different skill sets. There are people specialized in one field or the other. This way they are able to share their work load according to their specialized capabilities.

The work scale of such companies are higher. They have large number of competitors and to ensure profitability, they need best people who are masters in their skills. When they are masters, they can help better in the required work and eventually help the company to flourish.