How is that relevant to a discussion about worsening software quality? OS X never had native loopback.
I dont hear any detailed descriptions of how the software quality has declined. What I generally see is bugs being reported which is then called evidence that apple software is bad. I think the UMN story has shown that all OS software is large, complex and bug ridden.
I personally dont love how OSX is becoming more of a walled garden, but I also think that given the fact that bad people exist to make sure we cant have anything nice its a reasonable reaction to try and make the OS more secure. The days of the OS is your playground are ending. I wish that werent true but there are crappy folks out there that want to steal your data, identity, scam you, commit computer crimes against you.
I will reiterate that I think Big Sur was probably the smoothest big release of MacOS Ive been through(since Tiger). Others may have different experiences, but I can only speak to mine.
Additionally, the comment was in response to a comment about audio interfaces, so it's relevant on multiple accounts.
Handy when you need it, not exactly a metric for OS quality to offer one.
The fact there hasn't been native loopback for so long is mind-boggling. I'm a Mac user and use BlackHole.
I've lost count of the number of times I've been on a call and someone with a Mac has gone to share screen and been confused as to why their audio isn't being shared. COVID/WFH has made this a regular occurrence.