Which industry? Bonuses in the tech industry tend to be somewhat arbitrary and thus ineffective for motivating employees. Bonuses in other industries like trading or investment banking tend to be larger (sometimes more than base salary) and directly tied to individual performance and so they're highly effective at motivating ambitious employees.

Increasing marginal income tax rates on highly compensated employees might be a good policy overall. But where are we on the Laffer curve? If we go too far then it really hurts the overall economy.