As per our previous comment about department stores, an (alleged) drop in the sale of pants does not mean that young people are walking around naked. Instead, a change in lifestyle is at play. As sales of traditional pants - including dependable jeans - have declined, sales of leggings and other workout garments have increased. It seems that people are going straight from work to the gym, and therefore don't need other forms of leisure clothing to wear around the house.
The image this conjures is one of a young person who goes to work in business clothes, finishes their working day, puts shorts or leggings on, and then spends the rest of the day in them. We find this hard to believe, but the decline in the sales figures of pants is a fact, so there has to be something to it.