Hint: webhosts do not have to, IPv6-only clients can reach IPv4 only web services, and other services through well tested and implemented protocols like NAT64/DNS64. The other way around is not possible.
Hint2: all main stream OSes support IPv6 already, sometimes even by default set up IPv6 tunnels all on their own if your ISP does not do IPv6 natively (Teredo on Windows, f.eks).
You may very well have machines you use daily, connecting over IPv6 and you do not even know it. Did you read my link? About 70% of Verizone wireless clients now use IPv6, about half of AT&T. All new clients (cell phones, pads, whatever) use IPv6 by default, and some do bypass ISPs NATs with tunnels. Providers offering IPTV are moving to IPv6, new upstart providers offer IPv6 (because buying IPv4 is extra cost with little gain), old ISPs are in various stages of transitions... at what point should Amiga users start to worry?