I read the article. The distinction is indeed arbitrary. How much do you need for a base system really? Do you need more than the kernel, network drivers, and the filesystem? Last time I checked FreeBSD came with way more than those things. So someone, somewhere decided to include a whole bunch of other things as part of the base whereas they could just as easily be addon packages. I think FreeBSD includes various compilers and perl by default. Why's that? How is a compiler an essential part of a system? There are no apriori reasons to make certain "addons" part of the base system and others not. Linux does not draw this distinction and reaps the benefits of a more coherent system.

The equivalent of "base system" in linux land is called a distribution and rightfully so. There is nothing basic about a distribution. It is an arbitrary set of choices made by the distribution maintainers and it is sold/advertised as such.