Not all babies. My son found nothing fascinating for more than 2 minutes, he'd take it, work it out, throw it and I'd keep a constant round of toys going. He'd scream anxiously the whole time when not physically touching me, he'd cry until he vomited. Where possible is gave him in a sling but if I had to put him in a pram I would occasionally give him a screen. It was a last ditch attempt but literally nothing else worked.
My daughter? Fascinated by any small toy as expected, things held her attention.
My wariness with the links between attention span from my own life is that with my son I was adamant no screens, never even had the really on, did baby sensory, read to him, flashcards, sang in several languages, baby music class, baby swim class, trips out to library etc etc and he needed this constant I put all the time, couldn't just be left on a playmate or whatever. So I have him all the traditional input. His development was amazing, physically and academicalky but he couldn't stay still or be separate from me and even eating, cooking, cleaning we're almost impossible and I'm used to babies and crying but my boy, screamed u til sick, screamed into seizures later on. Had lots of hospitalisations and wouldn't watch cartoons etc even. But when he discovered gaming? The improvements were huge. His lack of attention span is WHY he was given a screen out of desparation.
My daughter? Games, puzzles, cuddly toys, just watching the world go by, as long as she was comfy and warm she was amusable as expected with a box of wooden spoons and pinecones.
I try not to judge unless there is obvious neglect or abuse because we're all parenting the kid we got and they are not blank slates at day one.