I think an additional thing being missed in loneliness, as described by the article, is that it doesn't consider that talking to someone via text chat or phone call is not that different in terms of fulfilling social interaction needs.
By the article's definition, I'm an extremely lonely person because I very rarely physically spend time with others.
But looking at pure social interaction, I speak to all of my family for hours every week and have been essentially constantly talking with a couple of online friends (who also share my interests very closely) for several years now, which would be completely unrealistic in-person. So I get lots of social interaction and it's all the sort that I really value. As a result I wouldn't really consider myself to be lonely.
Even when I did have a mainly in-person friend group, it was hard to meet outside of school since everyone has their own things to take care of, so it was usually easier for everyone to just interact via more remote-friendly means.