Human happiness is extremely elastic and subjective once the basic needs of life and essential safety from obvious, imminent, extremely visible threats are reasonably well covered.
This makes it easy to understand why many people self-report as unhappy despite having all measurable metrics of their material and fundamental existential well-being protected like at no time in human history.
Couple this with the bias in reporting on their subjective experience of unhappiness without ever having lived the harder kind of life that was normal in the past, for the sake of perspective.
Add to both the tediously demoralizing (unless you're resilient to it) effect of other social media-using humans trying to paint their lives as wonderful through selective reporting on a constant basis and all of this being visible for everyone else to see.
Also include in a moderate flow of (paradoxically) being saturated via media and social media with exaggerated, pathological over-focus on the dangers of generally uncommon problems and threats in life and the world.
The resulting pastry from all these ingredients: One very dubious notion of us haivng many more reasons to be unhappy today than before. We may think we have many reasons to be unhappy, but that's only because for the most part, we haven't seen what real reasons for deep unhappiness look like.
Obviously, i'm generalizing here. Not every unhappy person is unhappy due to frivolous things. There still exist many threats in life and many things that can bring on genuine misery, but they're more a minority now for more people than ever in the broad strokes of history.
One final point from all of the above: We're the source of our unhappiness. Technology is with rare exceptions just a tool, that we can use to interpret the world however we do, whether for bad or good.