The article argues that these factors have plateaued recently, not that they have reached any theoretical limit and couldn't increase due to future tech. The study authors seem bizarrely biased, claiming that it's very important for societies to make all people as tall as possible, as though that is good for something.
Barring significant medical improvements, of course. Designer babies will almost certainly be able to surpass those limits eventually and I wouldn't be too surprised if one of the many paths towards life extension technology pays off. (Senescent cell pruning, telomere extension/repair, whatever)
