See Apple Core Rot. MPG is the original source of this term, and first to report on the growing trend, starting back in 2013. The press at large is still in a murky state on this matter, barely grasping its importance or even its existence.
No professional can trust Apple any more not to break key tools at will, without a care in the world (at Apple) as the impact. Extreme engineering sloppiness (this has to be called incompetence at this point) has produced the worst possible kinds of security bugs in a steady stream: exposing cleartext passwords in (if I’m counting right) in at least 4 different ways in just 6 months such as this most recent fiasco.
The problems are not confined to big things. Little things, hundreds of them act together to make daily use of macOS anything from a headache to a chore.
I do not refer to the dilettante uses of a Mac where a user can just put up with garbage design for playing music and similar ( iTunes is truly a horrible design ranking right up there with Windows XP). Still even that is problematic. I for example listen to recorded books and I regularly (by mistake) touch the Shuffle button. Who in their right mind would want to shuffle the in-seriatum tracks of a audiobook? It is mighty irritating to go find track 37 on disk 23 again, particularly when it means pulling off the freeway. But seemingly no one at Apple must bother to consider such things (or has for a decade). Yet deem such things obvious to any intelligent mind developing software. I guess my 25 years of software development has made me too keenly aware of incompetence at all levels. Now I just get the stuff from Apple’s fan.
Speaking to professional use: I use Apple Remote Access to get to my servers. With the recent macOS security update, Apple Remote Desktop simply stopped working. Obviously, Apple did not bother to test how components interact (not the first and it won’t be the last time sloppy work will be foisted on customers). It cost me 3 hours to finally find a solution (reinstall the ARA 3.9.6 client software on the remote server, and do so in Terminal at the command line since I had no physical access to the server).
Do 99.9% of users care? Of course not, they do not use ARA. Does every server administrator naive enough to use an Apple product care? Heck yes. So this was a Big Thing that fortunately I was able to fix. I wish I could bill Apple for my time.
Then there are the little things. For example, reading mail in Apple Mail. I travel a lot and connections are often slow, so it matters a lot to me to know whether my mail has been downloaded and/or whether it is proceeding apace. In the screen shot below, the number might be "2" or "73" or "248" or whatever—I’ve seen it all. In every case, the actual number is zero (0) remaining, and this happens every day. A little thing? Not to me, but it is probably 3 levels down in priority on Apple’s fix list, if it is even on the list. Past experience of seeing up to 6 weeks pass before a bug report even gets an initial response make me unwilling to waste my time reporting—it will not get fixed. Bugs are to be added with each release, but rarely fixed.
Don’t get me started on how AppleMail destroys all my POP account configuration nearly every system release, and is so buggy that a special protocol to reconfigure is required, which fails 90% of the time—it can take hours repeating the process to restore functionality.
In MPG’s view, these operational issues speak to a company in decline. While it will take years, chickens do come home to roost.