IPv6 became a draft standard in 1998, and did not officially lose the "draft" status until 2017.
Hurricane Electric launched their well-known IPv6 tunnel service in 2001.
Google has published IPv6 adoption stats since 2008. These stats consistently show a greater fraction of users are on IPv6 on the weekend, because it's more common on mobile and home networks than office networks.
http://google.com/ works fine for me, tested in Firefox and with curl -6. So it could actually be your side that is broken, although it is probably your ISP's.
My side works fine, Google just doesn't like the address. It's a tunnelbroker address, maybe they consider that bots... but only for some of their servers? It's weird
I have all sorts of weird troubles with IPv6 at home. Facebook won't load some content, Netflix will frequently buffer and fail to load, Steam will almost never download things quickly.
Turn off IPv6 on my router, all my troubles go away.
It really isn't, but vendors often make the IPv6 config optional and often don't have an auto-config wizard for IPv6 like they often do for IPv4.
Take Ubiquiti EdgeOS, setting up a PPPoE with IPv4 has a dedicated GUI wizard that shows up when you first log on, but IPv6 config is all confusing CLI commands.