You assume the root servers are in control
They are not. Unless you run your own nameserver, you are depending on the delegation of the nameservers you use - probably your ISP's. If something "big" enough happens that the root server admins decide to take a walk, do you think they will all act in unison? Maybe, maybe not. Do you think that all countries will decide that's for the best, or that their governments or leading ISPs might set up their own alternate roots that become the defacto roots for citizens of that country?
The result of discord large enough to cause the root server admins to break from ICANN would probably fragment the internet. Maybe it doesn't matter for those in the west, since the US and EU are likely to be on the same page, but if you live elsewhere who knows where things fall. Sure, you could point to a different nameserver or run your own and choose the root you want, but you can do that today. Few do, because the alternate roots are mostly useless for general internet use (yeah there's the dark web, but that's 95% criminal or at least dark grey)
Sites like Amazon, CNN and the Register aren't going to set up residence on all the alternate roots that might spring up if the internet fractures. Large swathes of people might simply be cut off - they could reach them, but they won't configure themselves to be able to do so either due to ignorance or because they don't care to bother, so the effect will be the same. We might see a blog with spy photos of the next iPhone or something, that links to a site in China but we can't follow the link because it relies on use of an alternate DNS root we aren't set up for - and we don't know which one (maybe we'll need an http extension to list the DNS root in a URL...)
In a decade we might look back fondly on how small the internet made the world seem back in 2016, if the internet and web fractures into a dozen pieces down the road.