That doesn’t really make sense with the point of the article being that someone could be spending less than 30% of their income on rent and still not have enoug

That doesn’t really make sense with the point of the article being that someone could be spending less than 30% of their income on rent and still not have enough for their other expenses. If it was just rent being too high they would be over 30%. The suggestion here seems to be every expense is too high that even if you find the most dirt cheap sharehouse to reduce rent, you still might struggle.