Worldly Thoughts - Regionalizing Peering

Dave Siegel writes:

Since these are designed to be regional exchanges, one would presume that
transit is still available elsewhere.

Even at the large carrier level, I should think that the priority NAPs,
as well as the private interconnects, would contain complete information
on the other networks to back up any failure to route at a regional exchange.

Er, um, well yes, but ideally if you get peering from all the big
boys, you wouldn't need to purchase transit from someone.

I think the idea of only exchanging local routes at any given regional
exchange is not a bad idea, but I don't see how it would really end up
working properly in a fluctuating environment.