Headline is false. Slightly less than half of people make less than the "one-bedroom housing wage" calculated for their state, which is the amount per hour the person would need to afford a one-bedroom apartment if and only if you assume (1) they work only 40 hours and (2) live in an area at or above median housing cost for their state and (3) do not spend more than 30% of income on housing.
This article is either borderline propaganda or just terribly researched. Using averages in this way is just ridiculous. The assertions made are dismissed by common sense. The Guardian is usually decent despite their biases but this is some of the most absurd mishandling of data I've seen from them in years.