@Snakebite61 To play devils advocate here I feel like every generation since the dawn of time has had this opinion about the ones that follow.
If you think just about the last century: when people stopped routinely wearing hats in public, when it stopped being normal for men to open doors for women, or when children stopped being so frightened of their parents that they’d never question or debate them the way they often do now. I imagine plenty of people at the time felt “decency” was disappearing then too.
The same goes for “common sense.” Kids used to be allowed, even expected, to leave the house alone, run errands, or get themselves to school. That freedom helped build street-smarts. Today we’re far more cautious, so fewer people get those same experiences early on.
Technology has also changed what common sense looks like. With so much information at our fingertips, expectations shift. Most people would now check Google Maps rather than unfold a paper map and step into traffic, but that doesn’t mean earlier generations (or the ones who still prefer a physical map) lacked sense, just that the common part has changed.
And plenty of opinions changing hasn’t been a loss at all: attitudes to smoking, the way women and children are treated (mostly), and what behaviour we consider acceptable have improved enormously. It’s less that decency or common sense vanished, and more that society keeps redefining what they look like. I don't disagree with you that some aspects I also miss, but feels harsh to judge present behaviours by past standards.
Even just in the last ten years, since brexit for example, a lot of what feels like lost decency or common sense is tied to visibility and technology. Political disagreement has become louder and more public since Brexit, especially online, so it feels harsher even if people haven’t fundamentally changed. Everyday etiquette has shifted to; phones, apps and systems now do things we used to rely on memory or judgement for. When those systems fail, it can look like people lack common sense, when really the definition of what’s “common” has just moved. At the same time, we’ve gained a lot in awareness around mental health, consent and fairness, which previous generations often lacked. Can argue it both ways.