Oddbean

routers only need to know the address spaces out each port, it's not source routing this is why DHT can only do so much, at best a mechanism for matchmaking, the transport still needs ARP tables and whatnot ipv4 or ipv6 the architecture is the same, there is backbones, then there is network zones and then subnets and then LANs at the edge the biggest difference with ipv6 is the LANs have got enough addresses to not need NAT traffic still travels the same way, you just pipe it out the interface that has the matching netmask

in terms of negotiating the problem of NAT what we need is services that give people IPv6 addresses on their devices, and anyone connected to this can be routed inbound via the hosting services you can get a plain IPv4 inbound route with very little configuration on a VPS using wireguard as the client side outbound tunnel and all traffic for given IP/ports can then find the gateway and pop through the tununel it's a little outside of my experience area but i know in theory it would be possible to make a routing service that lets you attach a number of IP addresses to a network with like 10gbit, 50tb traffic and make a profit on proiding users with 10 or more inbound routeable addresses, more, if you include reverse proxying as well as port forwarding it just has to be charged on the basis of bandwidth mainly, to be economical, as the bigger your server/cluster capacity the more the bandwidth factors in the cost, and routing is the cheapest server hosting service for actual hardware requirements

https://www.rapidseedbox.com/ipv4-rental one can get a single IPv6 address for $15/month but for 6x more you can get 65536 addresses all you need is a few VPS running to provide adequate uptime and you could rent them out at a profit for like $2/month, just need an easy to install package to attach the device to it