What is the best word describing the nature of expiring in a short amount of time, connoting "losing public attention"?

I like the word fleeting for this:

: passing swiftly : TRANSITORY
// … the often fleeting nature of fame and fortune …
— Tom Sinclair

So:

In a fast-paced era, news articles are fleeting.

Of course, the referenced transitory would also work, depending on the style of speech to be conveyed.

I know there's an accepted answer, but another word that comes to mind (a synonym of fleeting) is ephemeral.

lasting a very short time
// ephemeral pleasures

One could use short-lived.

not living or lasting long

I think a better word for this would be evanescent:

evanescent adj
1. vanishing; fading away; fleeting.
2. tending to become imperceptible; scarcely perceptible.
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Right on both counts.