AES67 is just an interoperability standard, it's more of a device level protocol than anything. You buy AES67 compatible gear for your application, then use the vendors' tools like Dante Virtual Soundcard (so you can essentially treat the networked audio system as a normal soundcard on your machine through CoreAudio/WASAPI/JACK/etc).
It's actually pretty great, most of the time there's no need for a separate API just to handle streaming. It "just works."
Kinda? You need hardware at some point. AES67 was all about creating an open protocol for connecting different proprietary stuff, and frankly there's only a handful of places where I've seen open hardware worth its salt in audio. If you need high capacity, low latency audio over networked machines, you're going to need proprietary hardware/software in the chain somewhere.
