First off High Max, having money is good. Having money means you can buy things. Having more money means you can buy better things. You may not want to live in a nice house with a beautiful ocean view, but some people do, and you need money to do that as there is only so much coastline.
And Flipside, I wouldn't assume that. A business paying $100 million isn't intending for their employee to only make $10 million with 90% tax rates. They are offering $100 million because they think their employee is worth $100 million. Business don't set wage scales based on take-home pay for their employees, they set wages based on how much they are willing to pay for a certain amount of work. If a business is offering $100 million with 90% taxes, there's a good chance they will offer that same $100 million with 10% taxes, since the business paying the wage is still losing the same amount of money despite the differences in tax rates. Only, with higher tax rates the employee loses since a larger portion of their income is confiscated by the government.
EDIT: If we assume business pay based on take-home pay, then higher tax rates do make a difference in pay, since a business will pay less per employee for the same amount of take-home pay if taxes are lower. The employee still makes the same amount of money, and the business has more flexibility in money since less is taken by the government. The employer can either keep wages the same, possibly offering more than businesses that lowered wages to save costs, or they could lower wages and put that money towards more hires or new equipment, both of those increasing productivity and stimulating economic activity.