I'd be a little bothered with $300 million if I could have had close to $600 million instead - especially knowing that the difference went to the middle-men in the deal.
The middle-men (investment bankers, in this case) didn't make the $300 million profit - they sold it to people who manage money, that made the profit.
Typically, the biggest blocks of money for IPO investing will be institutional investors : meaning that the actual beneficiaries will be the pension funds, and investment funds of regular people.
The sources of profit to 'Wall Street' are the 7% underwriting fee (which is an enduring travesty, IMO) and performance fees on the managed money (which get a boost because the underlying fund appreciated step-wise).
Regular performance fees are mostly related just to the size of the fund (approximately 1%) - so the effect of the IPO jump on an overall fund will be negligible. However, individual managers potentially benefit indirectly because their performance relative to their peers would improve, and they may be able to get bigger portfolios to manage (which is the big win for an institutional money manager).
If the IPO buyers were hedge-funds, then they would benefit from a 20% performance kicker (which is why people at hedgefunds can be very handsomely rewarded). OTOH, the hedgefund investors would likely just be 'flipping' the shares within a couple of days - so they're less attractive/stable initial holders than the investment banks would ideally like for a 'solid' IPO.
