Tell that to the tech who can't read hex or the guy trying to find a network range in logs using sed/grep on an 80x30 crash cart terminal in a DC, because something broke at 1am.
It is wholly unsuitable to straight up replace IPv4 for these reasons: it isn't a human-accessible protocol.
Can't read hex? What? And who is speaking of "straight up replace IPv4"? Who is saying that? What are you responding to? If you want to use IPv4 on your private network knock yourself out. Nobody cares. IPv6 is only needed for public Internet.
That's what I meant by "which IPv6?" SLAAC, RAs, DHCPv6, authoritative DNS AAAA with reverse are all basic table stakes to make it useful, which already grossly exceed what small IPv4 business networks have for v4, and there's still another dozen services required to get full interoperability with v4.
"SLAAC, RAs" is the same shit. DHCPv6 is optional and AAAA records are no different than A records. All of the elements are the same and the protocols work the same way with only minor structural differences. Any router that is going to provide routing and DHCPv4 services is going to do the same for IPv6. You just have the added option of forgoing DHCPv6 if not needed. "Still another dozen services required"?? What dozen services? "to get full interoperability with v4" ... What interoperability? IPv4 and IPv6 are separate protocols that do the same shit. There are abstraction layers in higher level systems (DNS, Dualstack...etc) allowing both protocols to be used by higher level applications seamlessly but they generally do not interoperate. There were/are mechanisms that allow IPv4 to be a carried over IPv6 but they are generally unused.
And you're forgetting that IPv6 was never intended to run dual stack with v4, that was a hackish afterthought which didn't work for half a damn for over a decade, because v6 wasn't backwards compatible.
The ship sailed on compatibility the day a fixed size of the IPv4 packet header was cast in stone. The problem is address space not structure of packets, protocol design or any other consideration. Any change to increase address space REQUIRES global changes to ALL systems to maintain a network in which each peer is addressable by every other peer.
There is an insufficient space of possible addresses to meet demand. Either you invent some kind of extension mechanism with tunneling layers or you deploy a new protocol. The tunneling bullshit was not production quality and soundly rejected by the market. Dualstack works as a production quality solution that has been in widespread use for decades.
Needing to deploy v6 to "maintain a global network of peers" is only necessary if IPv6 exists; it serves only the purpose of sustaining itself.
The Internet is a network of peers and there is widespread value in this persisting. This value is not derived by the existence of any particular L3 protocol. Common applications include interactive games, P2P/file sharing, voice and video conferencing, remote access, providing information services..etc.