life is harder and crueler these days.

I think you just found the popular belief that I disagree with.

Compared to most of human history, life now is pretty good. This article uses childhood mortality (globally 4.4% versus 50% for most of human history) to make the point. There's still lots of room to improve - the EU has a tenth the global average - but humanity has made incredible progress on that front over the past two centuries.

Looking at a smaller time scale, the human development index is trending upward everywhere since 1990.

I can think of two relevant things that bear upon your attention here.

Stress, which makes your attention kind of jump around.

Temptation, which makes your attention go places without you choosing it. It's a kind of loss of control.

I think most people have always had short attention spans but technology has taken advantage of that to captivate us. History just tells the story of those who lengthened their attention spans on purpose. History is rarely the story of common people, it is often told by the exceptional about the exceptional and this distorts our perception of humanity significantly