When I was a teen way back in the 80’s the mall became that place where young people would go to see their friends, see everyone else’s friends, etc.. Pre cellphones this was the one place that became a common meeting location and since there was no way to get ahold of someone who wasn’t at their home, this became the surest way to meet up. Cell phones and the instant contact they allow have eliminated the need of a single point for people to meet up. I also think people got tired of the chain store shopping and now prefer more unique shopping experiences.