New was good because humans needed many things (that were new at this point). Now that we got almost everything we need, "New" is no longer good on its own.
Humans did not “need” things they lacked, and live to tell about it. Every age could see itself as complete. We’re fortunate that it took until the mid 20th century to freeze everything in amber. Unfortunately, the mid 20th century left us some really problematic stuff that wouldn't pass regulatory scrutiny today - like car dependence - and now we can't get rid of it.
Part of why they're threatened is due to lackluster planning and future mugging economics.