While that may be generally true, the perspective is too narrow, because the importance of these markets extends far beyond the largest participants in them. The market mechanism allocates credit and determines the borrowing costs of households, companies and governments. Proper market functioning is really a public good that relies on confidence and trust among market participants and the public.
Bad conduct, weak internal firm governance, misaligned incentives, and flawed market structure can all place this trust at risk. One of the ways we have to influence incentives is through compensation practices at supervised institutions. Many have argued that pre-crisis compensation practices at the largest financial firms allowed or created misaligned incentives.