[jonbarker]

I believe breakups would drive up the expense ratio which is why Bogle said that it would be damaging to individual investors. Part of the reason why Vanguard is so cheap to operate is because of its size contributing to economies of scale. You can see small variations in the expense ratios now (for example Fidelity is slightly higher cost than Vanguard across most apples to apples comparison funds) for this reason.