I think it's like anything else: it gives some very good suggestions, but if you feel you have to apply it in every single detail at every single moment it can actually make you less responsive to the children you actually have.
tbh I don't think there has ever been a time when mothers have been able always to respond at the exact moment to their baby every single time
even in prehistoric times, mothers would also have been busy with older toddlers, climbing trees or fishing, or tending potentially dangerous cattle
and I suspect even in prehistoric times there were some babies who showed quite clearly that they were happier with a little less contact, who rather enjoyed being laid down
The idea of children's innate self preservation instinct also seems a bit dodgy to me
or rather, though a fairly laidback parent, I am not sure I am prepared to pay the price in terms of prehistoric proportions of child mortality
I am more of the First Teach Them To Be Safe, Then Give Them Indepence- school of thought.
I spoke the other day to someone who recounted experiences from a traditional African society and she said that the number of accidents are horrendous because toddlers are basically left to look after themselves, so you'll find 2 and 3 yos wandering around the street looking for their parents: this is a society where 4 in 5 children do not reach their tenth birthday
she compared it to the large number of (in our eyes wholly preventable) accidents that you find in coroners' reports from the Middle Ages
What I have found myself as a parent was:
one of my children enjoyed the constant velcro contact; the other did not
one of my children did well on demand feeding; the other was not strong enough to demand to be fed often enough but needed to be woken up and made to feed (when I tried demand feeding she lost weight rapidly and ended up in hospital)
one of my children was physically not capable of the same amount of physical freedom as her peers: when I tried it, she ended up unconscious in hospital; the other one has never had a real accident in his life and could safely be left to make his own decisions
one of my children responds well to a quick telling-off and subsequent reconciliation; the other feels humiliated and needs a bit of face-saving humour to diffuse the situation
Nothing imo compares to being responsive to your individual child.