IPv6 could have done three things. First, embed the "legacy" address space. Second, have legacy-to-legacy connections use v4 on the wire. Third, strongly encourage existing user-maintained configuration (config file formats etc.) to remain perfectly valid as long as they don't use v6 addresses (or other v6 features.)
You are right, you'd still need a "legacy" address to connect to "true" v4 servers, but that address would be all you need, while most operating systems, routers, client and server software could be, technically, all-v6 all-the-time by now.
You are right, you'd still need a "legacy" address to connect to "true" v4 servers, but that address would be all you need, while most operating systems, routers, client and server software could be, technically, all-v6 all-the-time by now.