My 8yo DESPISED tummy time. NEVER did it (beyond a few goes) until age SEVEN. <laughing> Seriously. He would hold himself completely up off the ground on arms and legs rather than let his stomach touch the ground.
He was a late(ish) crawler and a late(ish) walker, and a late(ish) talker... and *extremely* early with head holding (day he was born he had total control over holding his head up and looking around, fine motor (fingers, tongue, facial expression), understanding (he didn't talk a lot but he communicated just fine), reading (3rd grade level before age 4).
Now... my family is crawling with healthcare professionals (doctors, nurses, a speech pathologist, etc.)... so we were totally unconcerned with his development. It was very obvious that he was working on x instead of y, or y instead of z. He hit milestones all over the place (like most babies do, it's part of why there's such a large range)... and has turned into an extremely physical very smart little guy. Who just never spent any time on his stomach.
If your family ISN'T crawling with experts... head on over, and let them see if he's just working on x instead of y... or if there's reason to be concerned.
One of the SEVERAL things that bothers me with this article is the "THAT'S THE CAUSE!!!!" aspect of it (there's never just ONE cause to any complex system), the generalizations it makes as if fact, and the total lack of historical knowledge, ((100+ years ago people kept their babies confined on PURPOSE to slow down physical development. Think papooses. Ideally babies didn't crawl until over 1 year old... and they were kept in nursing gowns until apx age 2 -which was the normal age for starting walking. BUT cognitive and emotional development as well as speech and language development was MUCH earlier... most children were reading fluently by age 3 in educated homes, for example, and we're talking language of the constitution level of reading, not Dick & Jane... and some of our greatest thinkers and athletes came out of such a childhood.)). It's a sensationalistic article with very little basis for it's claims, depth of subject, blah blah blah. It's a "get parents riled up"/ fear mongering kind of piece I find particularly nauseating.
I can think of at least 5 common contributors WITHOUT EVEN DOING ANY RESEARCH, and can counter each of it's points with at least 3 arguments and that's, again, without spending any real time at it much LESS digging out physiological, anthropolicial, or sociological studies.
Pfui.
It's pulp.
((excuse my snarkiness, that kind of bad writing/bad science just makes my teeth itch))