The ordinary meaning of intelligence is about joining the dots: when X happens again, you remember that X happened before, ten years ago, and have the wit to notice the similarities and differences between this time and last time.

Intelligence tests are tests of quick-witted puzzle solving. Does an IQ test involve getting the subject to memorize something, then coming back a year later to see it they still remember? No, it is all done in half a day; no long term memory required.

So why do IQ tests and the ordinary meaning of intelligence line up, when you need long term memory to be intelligent in the ordinary sense? I think it is partly coincidence; among the humans of today, good long term memory and quick-witted puzzle solving ability are strongly correlated. And partly about brain health. A healthy brain does both puzzling solving and remembering. Testing puzzle solving tells the tester about brain health, which tells the tester about memory.

You are noticing the correlation breaking down. My guess is that peoples memories have got worse. They respond to each news story as it comes, solving the puzzle of what they are supposed to learn from the story as presented on the day. But failing to remember earlier stories, presented differently. Maybe memory is worse due to lack of use. People just look stuff up. And if Wikipedia has been edited, they don't remember the old page, and don't notice the change.