These 'beginners' are building working sites left and right every day. They don't need to feel they are on the bleeding edge of html, they just want their stuff to work reliably with a reasonable cost. Most of them don't write blogs, don't have githubs, don't own node packages. They develop web sites the same way that you and I drive our cars. They adopt jQuery without a second thought, and why shouldn't they?

jQuery's extreme ubiquity arguably makes it the de facto DOM abstraction library, and this does conform to the definition.

Its demographic, or target audience, is irrelevant, because it is everywhere, and much to the detriment of 'pure javascript' (some might argue).

It'll remain that way until differing browser implementations converge and obviate the need for an abstraction that papers over the cracks.