This begs the question: What value do 'private' interconnects/exchanges
provide? I would submit that the answer isn't readily acknowledgeable, or
at least, has not been explored to the extents necessary.
One Big Win (tm) with the creation of local interconnects (for instance,
strategic locations in Asia & South/Central America), is that local
content providers can find a way to swap bits without transiting all
the way back to the United States; in my opinion, we need more exchanges
to decrease the amount of traffic contributing to this problem.
The value of private exchanges/peering between the larger global providers
is that they can get traffic off of their backbone before it reaches exchange
points which are already glowing in the dark. I don't think this needs much
explanation.
Part of the problem is that, the more BGP peers, the more the statistical
chances for instability. Unfortunately, I don't readily see a solution
to this particular issue, if large providers are not economically
incentivized to build more, smaller interconnect points which allow
tier-2 and tier-3 providers to peer with them.
Then again, I don't pretend to understand *all* of the corporate
political, technical and economic, issues. 
- paul (en route to Ann Arbor)