But YES PLEASE if it means we don't have to deal with endless new bugs introduced by their heinous QA of lately .. APFS, root logins, &etc.

I would expect that the wholesale change from Darwin to Linux would introduce an amazing number of new and awful bugs. It's not like their development processes will suddenly be fixed when it's been touched by Linux.

I believe Linux (the kernel) has one of the most productive, QA production lines out there. If Apple were to adopt the "Linux way", we may indeed see a change ..

On the other hand, it may work against us, having Apple involved in Linux things. I'm not sold either way - but I sit here, re-installing MacOS on two Macbook Pro's, both of which absolutely refuse to make a usable/safe disk image out of their own disks. This is such a frustrating conundrum, it feels like Solaris in the 90's. I can only hope something changes at Apple, or else I'm just going to wipe MacOS and put Linux on these machines. That is quite a watershed, imho.

Have you run a drive test? If you're having storage errors it could manifest itself in weird ways.

Yes, I've done it and Disk Utility doesn't think there's anything wrong. But yet, I've tried over and over to make a disk image - of different disks, even - and every single time I get the error "no usable disk image found". At this point, after having scoured the web for clues, I can only conclude: this is a bug in MacOS.

I'm now trying to do a full update to the latest release, and see if it works beyond that point - but if it doesn't, the good ol' tarball approach is all I've got left.

I think Apple has some QA issues.

Does it have anything with kernel? I thought that those bugs are mostly userspace.

The one recent kernel bug I remember is poll returning early:

https://daniel.haxx.se/blog/2016/10/11/poll-on-mac-10-12-is-...