Because we don't own people.

cos you would have a price on your life

Because its not a tangible asset, you could not sell staff if you require income. Also if the level of business drops off, they become a burden on the company because of redundancy pay etc. It has important place in productivity reports and efficiency of staff.

Many business tend to focus on balance sheets, as that is the ultimate goal of a business. You focus on different area's to improve the balance sheet. Often profit is increased more by focus on the effectiveness and efficiency of the structure & staff of the business. Its not a moral issue, just a practical one.