v4 and v6 were build around the exact same use cases.

> With v6, everyone is effectively in the same network.

Just like IPv4.

> I have to ask my ISP for a prefix that he will rent me for money even for my LAN.

Just like IPv4, if you need a static address.

> If I want some freedom from said ISP prefix, I am mercifully granted the honor of managing ULA/NAT66 (granted I paid for a fancy router).

Compared with IPv4, where if you want some freedom from said ISP subnet, you are mercifully granted the honor of managing RFC-1918 addresses/NAT (granted you paid for a router that doesn't screw it up).

> Also if I want any kind of privacy, I will have to manage privacy extensions

...which are enabled by default nearly universally

> and the great invention of having to use automatically generated, dynamically routed, essentially multiple random IPs per interface.

Make up your mind. Are rotating, privacy-preserving addresses good or bad? The way it works in real life, not in the strawman version, is that you (automatically!) use the random addresses for outgoing connections and the fixed addresses for incoming.