So by natively I mean that if you look at the packets there is only ipv6. 6rd, hurricane electric and so on, you can use these tunnels to get the functional equivalent of having IPv6 at home, but between you and the point-of-presence (the other end of the line your router is connected to where Swisscom decide to do something with your packet) is IPv4.

Customers actively have to opt in to 6rd on Swisscom and actively have to set up hurricane electric and other IPv6 tunnels. Which means connectivity is limited to people who are going to do that, so service providers on the internet must offer IPv4.