It’s true. I teach college kids, and a couple of years ago my class was taking a midterm. The room didn’t have a clock so I put my watch on the document camera display so they’d know how much time was left. A girl in the front row asked me what time it was, because she couldn’t tell time. After she turned in her test, thinking she must be kind of embarrassed about this, I told her I’d be happy to teach her how to tell time. She gave me a look like “ok, boomer” and said no thanks.

Or, the window of habitability on Mars was much shorter than on Earth, and there just wasn’t time for complex, multicellular life to evolve. On Earth, life existed for billions of years before multicellular critters popped up. I think one day, a rover is going to turn over the right rock and we’ll see a little smudge of fossilized algal mat. But I am an optimist.