I think in a lot of instances it is genuinely because things are getting stupider, and I often feel like the internet is becoming a major contributing factor to everything becoming way more shit. You would think at least it could somehow preserve and spread more international culture but instead all I see is greater levels of stupidity and atomization.
Die Hard movies never actually intended to be anything great, but at least the first and secondly were passably good fun, in spite of a few retarded hoo ra usa #1 shit like the "eurotrash terrorists", which I think happened around when Cold War ended so everyone was confused who to make a villain. But the last Die Hard suffered I think the most from being a post-9/11 film, which frankly wasn't even that big a deal but the whole weepy "we're the worst innocent victims ever this is worse than the holocaust!" crying eagle propaganda shit went into overdrive as did our tyrannical laws and society has never recovered from it--not from the terrorist attacks themselves, but from our own government and toxic culture it helped spawn.
There are a lot of other reasons for things being dumber and in the case of Die Hard movies it is just typical sequel deterioration but yes everything has sincerely gotten both dumber and trashier over the last two decades particularly following the Columbine-9/11 shit. The worst is the combination of creeping anti-intellectualism which while embodied by poltards is pretty society wide, coupled with rampant soulless consumerism.
Which is all a shame because never before have we had such great potential for science and culture but it's all being wasted.