US ownership of ICANN
...will likely continue as a very useful point of leverage, until this country goes broke (which, at the current level of borrowing, shouldn't take more than another 5 to 7 years at most).
please note that there is nothing (except maybe technical competence) stopping other countries from getting together and redirecting all DNS queries to their own servers that spoof like TLD roots. it would take some hacking to change all their core routers at approximately the same time, but if managed properly, there is no technical reason why it can't be done.
careful coordination and timely action will be required, along with meticulous preparation (zone transfers, registry spoofing, etc.), several trial runs on isolated networks, and then a near-global cutover.
properly executed, this would bypass the current root servers completely, while duplicating the functionality in a parallel spoofed structure.
this would be somewhat more difficult after secure DNS is implemented, but it would still be possible.
fortunately for the US, the rest of humanity doesn't cooperate worth a damn. unfortunately for the US, "things that can't go on forever, don't" (a statement made famous by Herb Stein, an economic adviser to the Reagan administration). at some point, this structure will have to diversify; let's hope it's not at the point of catastrophic failure.