I'd argue having to run STUN and TURN relays imposes additional costs on service operators and therefore increases centralization instead of decreasing it. Furt

I'd argue having to run STUN and TURN relays imposes additional costs on service operators and therefore increases centralization instead of decreasing it. Furthermore, if Amazon (of all companies) was pushing for IPv6, we'd see a little more IPv6 support at least on their public endpoints, as I commented elsewhere. As for public reachability, most OSes have a firewall of sorts (nftables, pf etc.) and can be configured to block traffic by default; on consumer OSes they already do so. There's also the local unicast range fc00::/7, which seems conveniently forgotten about in these kinds of comments.