There is no "transfer" of anything. Anyone can edit the root.zone file. I use my own curated version. Great for blocking ads, etc. But for many years no one did this, except very rarely. And the honors were left to some folks in the US, IANA/ICANN. Do not be fooled by the acronyms and the fabricated processes and formalities on the official websites. IANA was essentially one person. Bless the hearts of those who work…
Someone has to do that job for it to all work. Do the managers of the hundreds of TLDs around the world contact you to update your version? No, they send them to IANA.
The IANA's job is simply to be the authoritative repository of unique identifiers and associated configuration data — TLDs, IP addresses, port numbers, MIME types, etc. You are free to use your own bespoke IP addressing scheme, port numbers and MIME types too, but don't expect to be able interoperate with anyone else.