You can certainly try to do it with anything you like, Sealand included. The real work is getting others to agree or care. Handshake has some preliminary support, and more, it seems, than any other project in recent memory.
Alternic once tried, as did Namecoin. IIRC there was also an alternative PKI root that some hackers tried to get going, but no browser ever incorporated into the trust store.
Anyone can try! I'm not saying Handshake is, like, illegal. But it still seems like... a scam? I'm not sure what the word is.
I'm still waiting....
Moreover, ICANN-affiliated industrial cartel is trying to keep this for-profit status quo, as exemplified by njal.la registrar operator Peter Sunde being denied ICANN accreditation despite being well-known (despite my political disagreements with him) as a good-faith actor [2].
[0] https://dzdb.caida.org/tlds/graveyard
[1] Forgot which as i haven't been affected, but HN folks will probably find links to comments on here talking about.
> They're actively thwarting ICANN's overreach and centralisation of control by redecentralising the internet again.
I'm all in favor of that. ICANN and its affiliated TLD/registrar mafia is screwing everyone. However, Handshake depiste the good stuff (distributing lots of cash to free software project) is not effectively decentralizing DNS governance, it's centralizing it in different hands: who controls the Handshake source code? what is the treat model of its blockchain in regards to Sybil attacks? Can the persons with the biggest wallets control the network? If so, it sounds like ICANN all over again, with "coin" speculation added on top.
> a legitimate use case for a blockchain
A blockchain in itself has many usecases as an append-only ledger. However, i've yet to see a legit usecase for a public blockchain, because trying to establish global consensus among unlimited untrusted peers is "hard" to say the least.
DNS sounds like a good usecase for a DHT, where Sybil-resilience has been better researched in the past decades. The root zone would simply be a well-known entry in the DHT, much like it currently is a set of well-known IP addresses and DNSSEC keys.
I strongly recommend you watch ICANN's "Emerging identifiers" session [0] from ICANN66 where both Handshake and GNS are presented. I found it very informative that Handshake is more concerned with the domain acquisition process (auction) while GNS is more concerned with solving actual problems we have with DNS (security and privacy).
[0] https://icann.zoom.us/recording/share/M8N-Duq935XheIZoBedIwm... <-- sorry for linking to Zoom, it appears ICANN doesn't have a Peertube yet