Equinix and S&D (PAIX) will be the new peering exchanges.
I hate to think how many exchange points that leaves out. Telehouse and Terramark come to mind. Even if there are some dominant players, domestic neutral exchange points are still a diverse, vibrant market.
Question is, outside of 6 exchanges domestically, what scenario would force a move to doubling that to 12. Long haul circuits rising again, or perhaps some new killer app. Right now seems domestically 6 may be all we need.
I'm putting the number closer to 40 (the "NFL cities") right now, and 150 by the end of the decade, and ultimately any "metro" with population greater than 50K in a 100 sq Km area will need a neutral exchange point (even if it's 1500 sqft in the bottom of a bank building.) -- Paul Vixie