Professional PA is (almost) exclusively Digital those days.That's a digital mixer, though. I thought we were talking about analog PA gear.
You have System Amps with DSPs calibrated to the speaker (or activ speaker) this Amps Normally take AES3/EBU.
A audio interface with "network" ,Danke, Dsnake, AES67, AVB...
Its a mess! right there is no widely adopted opens standard... that's why AMPs and speaker still use AES3 for audio and Ethernet just for configuration and monitoring.
TL;DR its all Digital this days
That's why you would find it in the professional Fetish/Recording Studio.these days in analog is a fetish.
But 10-15 Yeas ago this was totally Different
Every monitor channel head some thing like this:
It was a pain!
Back in the days i saw a lot of BSS and DBX EQs, dbx where considered not as good as BSS.
So i don't think this is true at all.PA stuff is generally of poor quality by ASR measures
Maybe if you look at 10-20 Year old Low end hobby level stuff From company's like Behringer.
But if you look at professional gear from for example "l-acoustics" i don't think this statement is true at all!