Ah. K, I think the differrence is that I'm the outlier. Your system has far larger components, with more moving parts, which I think is more common:

On most of my systems, I'm not running any graphical system; they're all servers. That eliminates a huge amount of stack that can fail. On all but non-servers I run X, which is very stable (in that upgrades almost never impact it) on non-Nvidia GPUs. And of those, all but one run herbstluftwm - Gnome and KDE are both large systems with a lot of moving parts, any of which can break (or be broken) -- in your case, it was Plasma, a KDE component. And the last desktop is running Budgie which, while still Gnome, is a lighter one based on the older GTK3. All of these things tend to make for more stable systems.

But, most people are probably running fancier, full desktop software. Larger, more complex, more development, more frequent changes. And, consequently, more prone to cascading packaging breakages, like the Plasma one.

I think if I were using software like that, I'd consider either giving up Arch and using an immutable distro, or using something like snapper or timeshift that allows boot-time system roll-backs.