If you answered that the South American turquoise swarklebug is a swarklebug with a turquoise shell whose home region is South America, you won!
A Wikipedia article whose lede doesn't begin with that degree of simplicity, obviousness, and hyperlinking is usually ripe for improvement.
How many examples can you find and fix today?
Ontology in general is complex, and we aren't going to "reach the end of it" on Wikipedia; but applied or practical ontology is a big part of the difference between (1) being ignorant, or being only narrowly educated in certain areas, and (2) being broadly and deeply educated. And most applied or practical ontology is oddly simple, once you've figured it out, despite seeming mysterious before that. Often it is only a matter of recognizing, for example, that there are wikilinks that should be in this lede, but aren't yet. And it's not that hard to realize that in the article on (say) iron oxides, the words iron and oxygen, with links to those elements' articles, should be in its lede—indeed, in the opening sentence of that lede. It's not even hard. In fact, if you have solid 101-level scientific literacy, some critical thinking, and some basic composition skills, you can usually find ways to improve Wikipedia literally as fast as you can read it, in articles below GA status. And yet Wikipedia to date is still full of ontological gaps. Which (if you think about it) reflects on us humans, the default ways we tend to think, and what low-hanging fruit is available in improving upon them, even while acknowledging and accepting their humanity. And most practical ontology could be greatly elucidated at Wikipedia and Wiktionary (the two working together) if enough critical thinkers worked earnestly on those projects. Imagine a world in which 99% of the practical ontology that most people ever need was fed seamlessly to them, instantly, for free, and on demand, by Wikimedia projects. It would mean that when they land on the article about the South American turquoise swarklebug, they are going to understand within seconds (not by doing a bunch of further research) that it is a swarklebug with a turquoise shell whose home region is South America. And within only a few degrees of separation that can be jumped at the speed of a hyperlink, they will be able to tell, if it occurs to them to ask, what other kinds of swarklebug exist, what other things exist that are turquiose, where South America is, what an insect is, what other insects live in South America, why turquoise is called turquoise, and so on. Wikimedia can facilitate that, if people will simply bother to build these projects. We are not there yet—not nearly. You may find portions of Wikipedia that feel like they have arrived at that juncture—for example, the iron oxide articles of the Wikipedian world mostly already say "iron" and "oxygen" in their ledes—but I can guarantee you, from being one of the volunteers working away, out in the weeds, that in some of the areas that matter most to human health and economics, we are not yet even close.
Not yet close; in fact, there is so much low-hanging fruit around that sometimes, while I am picking it, I am troubled by the thought that out of something like half a billion to a billion native and ESL English speakers in the world, so very many of whom could be working on the English Wikipedia for free at any time they were willing to be and had a device and internet connection available to do it, I am the only one within the past decade who both thought of the fact, and bothered to take care of it, that the article on molecular biology, for example, should link to the article on molecules in its opening sentence. The funny thing is, it doesn't take much. A mere high school education, some curiosity, some thought, some reading of books and googling of connections, is all that's required for most of the improvements I make to Wikipedia. I myself went to university, too, although I'm now making up for the deficiencies of my experience there, slowly and on my own. Anyway, the point being, anyone with half a head can do this, and it's kind of sad that so few are, considering how much nearly everyone benefits from the existence of Wikipedia, both directly and (even more importantly) indirectly. It troubles me that we have such a fat, wonderful opportunity in front of all of us, waiting for nothing but for smart people to bother, and it's lying here so largely unrealized—quarter-realized or tenth-realized, compared with what it obviously could be if more than 0.1% of capable people were bothering. And yes, people who don't bother could point out that I'm spending my own time doing this, and at what opportunity cost, and Wikipedia has errors in it, and on and on, but let's get real here—what the hell are countless other people doing at this very moment with their allegedly precious time? Posting shitty political image macros on Facebook? Watching action flicks and playing active-shooter video games?
If you think that that sounds like a whole lot of bullshit and you'd instead like to do something useful and educational and positive and peaceful and self-improving and altruistic with your life, grab a hoe and come help, out here in the weeds. It's fucking free, and there's fresh air and sunlight.
PS: Speaking of the theme of "shouldn't this already have happened by now?", see also "Shit I cannot believe we had to fucking write this month" by Emily Temple-Wood ("This month in systemic bias, we had to write a whole bunch of shit that should have been written forever ago and generally made the world a better place.")