No, they don’t. The root server owners (who are mostly universities and research groups, last time I checked) have no formal ownership over the DNS network. They cannot seize or stop any participant in the network, including your scummy local ISP.
Confusing the TLD situation for ownership is making the same “distributed, authoritative” mistake.
Despite what blockchains have been showing, decentralisation doesn't have to be painfully disruptive, behave erratically, look like a complete failure or be a thinly veiled centralised system in order to be considered successful. It can also work well and smoothly!
Yep, this is the irony: the Internet (and WWW) are still mostly decentralized and distributed in the classical fault-tolerance senses of the words. They're held together with patch cables, anxiety and pager calls, and they still work better than anything the cryptocurrency space has managed to produce in the last decade.
Confusing the TLD situation for ownership is making the same “distributed, authoritative” mistake.