Every IPv4 packet needs a source address. If the client is IPv6, what is the IPv4 source address?
You would want to assign an IPv4 address to the client transparently; and, since they're scarce, share it with several clients. That's what NAT64 does.
No, because chips, by design, can't be copied by the user. They are roughly small computers which encrypt messages with a secret key, but the key itself is never let out outside the chip.
You would need some cooperation from the card issuer to clone the card, or some sophisticated technical equipment to open up the chip and read it.
Since Google dropped Jabber server federation, open XMPP are less useful.
And, for voice/video, getting them to work through NAT is a pain, while Skype JustWorks™. Plus, it is a really good solution: I can change my connection from WiFi to cable, and the video recovers within a few seconds.
That said, I'd love it if everyone ditched propietary solutions. But, unless you really care about privacy and freedom, it's a hard choice to make.
They did backtrack, but because of PR reasons, not legal ones.
Unless there are antitrust issues, it's perfectly legal to offer different prices to different customers.
Actually, most warning implementations punish those users that disable cookies in their browsers by forcing them to see the obnoxious warning every time they visit the site.
This is arguably worse than the previous situation.
You can keep DDG as your default search engine, and use the !g bang command to redirect the most difficult queries to Google. You get the best of both worlds (except for some cognitive load when deciding which engine to use).
You would want to assign an IPv4 address to the client transparently; and, since they're scarce, share it with several clients. That's what NAT64 does.