Or the gap goes unfilled. We live in an age where small diskless devices are uncommon and another type of small device now called "phone" is common. A small device nowadays doesn't boot from PXE+TFTP, it has its own SSD and doesn't even trust the network.
Maybe on your home LAN, but IP desk phones are increasingly common in offices (if we ever go back to those).
> DHCPv6 does exist, but I don't really understand what it offers over RA+ND.
How does RA/ND solve the problem of client auto-configuration of services? Rightly or wrongly, DHCP has been traditionally used for service discovery ("Hey! Here's some NTP servers, a TFTP server and a SIP server") as well as config discovery (useful for autoprovisioning of many devices) and I didn't think you could achieve that just with RA/ND.
Has anyone managed to get netboot or PXE working on IPv6 without DHCP?
Edit just saw a sibling thread about DNS adverts in RA. I guess RA could do all these things, but if it doesn't support it today, DHCP is going to fill the gap.