People don't want to buy stuff that doesn't give value over what they currently own.
New phones that offer nothing really new over what they own.
You don't need multiple copies of the same book, and you don't want to waste time reading authors that people consider less interesting than the ones you currently keep up with.
And I believe it all also goes back to consumer confidence, there are reports that people are beginning to spend like they did just before and during the last economic crash. Priorities are going to dictate where your money goes at that point.