In the link you provided, it literally says it's 5:3. It even has its own line in the infographics. And while the article is titled "List of common resolutions", it looks more like an exhaustive list of almost any resolution that has been ever used in any kind of consumer device. It's definitely not limited just to standard computer monitors so that table isn't really that relevant to the topic of the discussion.
Also show me a monitor with the 1280 x 768 resolution that's currently available on sale.
You're picking up some extremely rare cases to make an argument that your initial statement about "usually different aspect ratio" was correct but that's not how it works. That's just moving goalposts.