I like my Macs precisely because they are boring and almost never surprise me.
TBH, the only reason my Linux boxes surprise me is because I try stupid things such as mounting /var/log as a tmpfs to reduce write loads (mostly on RPis SD cards and eMMC devices).
I don't know about that — macs have enough weird behaviours that it wouldn't totally surprise me if, soon, they required a network connection, or the lack of one would at least make things awkward. For example, the inability to use clamshell mode without AC power.
Amphetamine[0] lets you prevent sleep on lid close. I presume it lets you do so without AC power (but I might be wrong on that), but one of the techniques they use to do that (setting the IOKit key that indicates the system is currently in clamshell mode) definitely does work without AC power. I made a command line utility[1] for myself a while back that does that if you're interested. It works fairly well, but the clamshell state tends to reset upon gaining/losing AC power. That's fine if the lid is open at the time (as the utility just applies the change again), but if the lid is closed, the system sleeps until the lid is opened again (at which point, it reapplies the change and you can close the lid again).
Q. a local mac repair shop installed "new OSX" on a laptop by request .. but it is version 10.12.6 (?) ..
Later, when downloading several common desktop applications, upon opening them.. it says "this software requires v10.13 or later" .. I assume this is completely on purpose to get the legions of happy Mac owners off of their stable OS and into the upgrade churn ? I assume (US here) you have to have to buy OSX 10.13, register an ID with Apple, to get new software (according to them) ?
macOS upgrades have been free since OS X Mavericks[0] (10.9, released in 2013). macOS 10.13 (High Sierra) came out in 2017, so is a 5 year old OS at this point[1]. It also supports all Macs that macOS 10.12 (Sierra) supports[1]. And you don't need an Apple ID for anything other than Apple services and the Mac App Store. OS Upgrades don't need an Apple ID (even on older versions of macOS where they're installed through the Mac App Store), and you can even network boot a recovery image and install the latest version over the network[2] (Intel Macs only).
I'm a bit confused by the question and might be misunderstanding but there is no need to buy OS X upgrades, they're free. But you do need to register with Apple to get them.
You’re not entirely wrong; you do need “Xcode Command Line Tools”. Thankfully, that’s a much smaller bundle than Xcode. It contains a bunch of tools for building code, such as llvm, ld, make, and git.
TBH, the only reason my Linux boxes surprise me is because I try stupid things such as mounting /var/log as a tmpfs to reduce write loads (mostly on RPis SD cards and eMMC devices).