I hesitate to make an analogy, lest the analogy wars begin...
Sometimes I am forced to use a telephone. I periodically get dead air or a fast busy. Sadly, my phone skills are rusted. Can someone please tell me how I select the switches and trunks through which my call is routed? Thanks.
Oh, and for those who might suggest "calling card": It doesn't work as often as one might hope. There have, however, been times where PCS to CC to local number gets through when PCS to local does not.
It appears that endpoints generally trust networks to... well... run the network. Don't like it? Build your own network. Now we're back to PI space and table size.
Moore's Law! (Anyone up for corollary to Godwin's Law in which the trigger is "Moore's Law"?)
In the "radical proposal" thread, the bottom line was that providers would rather have big[ger] routing tables than cooperate. Fine. It appears that we're now pitting routing table size against handing over control to endpoints.
Detection of sarcasm and hyperbole is left as an exercise to the reader. 
Eddy