> These aren’t complex proprietary standards,

They aren't proprietary, but they are complex standards, and sometimes somewhat incomplete. AES67, for instance, is somewhat crippled by not having a control plane (for that you need AES70, not well supported, or various NMOS standards). AVB requires special network switches.

Behringer doesn't really refuse to support standards. They offer Dante and MADI cards for their X32 and Wing mixers. They have AES50 built in as well. I think StageConnect and UltraNet are intended to be a cheaper/simpler/more limited alternative for people who don't need the full physical range and flexibility of Dante.