Yes, that's the one. The one published in the BMJ. Pulled apart because it was funded by the infant foods industry. There were, unsurprisingly, lots of threads about it on MN I think.
Yes, what I found on a quick google at lunchtime suggested 2.5-3.5 years rather than 4.5 years which was Katherine Dettwylers assumption based on many different comparisons I think. Still years and yes, I agree, nutritional benefits might not be as great once weaning onto solids starts (we'll ignore the 4/6 month thing for now) but as it has been pointed out on here numerous time, BF beyond 4/6 months a year is about far more than nutrition.
Antibodies, nutrition, comfort - they are all still there so why should women be made to feel weird for choosing to continue giving these things to their babies via breastfeeding?
I am not saying people should feed their children past any age they are not comfortable with or at all if that's there choice but to say that extBF is weird, perverse or has few benefits at 4 months is wrong.
Formula/cows milk (as we drink it) is always the same, its contents do not change to meet the babies requirements, combat illness etc. A strong positive in support of ExtBF but not addressed in the research you quoted I am sure. That focuses on nutrition. BF is more complex.
And yes, domesticated cattle & women being allowed to wean their babies earlier can be super, gives women choice etc etc doesn't mean we should have to wean or are weird for choosing not to. It also doesn't mean it's as good or better for the baby.
The argument on the thread seems to have boiled down to extBF is weird, has few benefits and is comparable to other non-human milk products and what I am trying to say is its not. Can you agree with that?