Trying to think of the one western culture I know well which has genuinely high rates of breastfeeding (though ime often with the occasional bottle of formula).
In Sweden I don't think there is a plethora of mothers and aunties milling around the new mother with cups of tea and advice, at least no more than in the UK. Women tend to be out at work until they reach 65, so there are far fewer women around in the daytime, except the ones who have just had babies. And couples don't tend to live close to their parents, any more than they do here. Families are usually no larger than here, so most people will not have watched several young siblings being breastfed.
What there is, however, is a far higher level of involvement by young dads: partly because of the generous parental leave, partly because men tend to be far more involved in running the household at any time. You just don't hear the "oh, dh couldn't cope for a day without me, he is so clueless"- a woman would be ashamed to let that be known (unless they are about 95) because it would make their family stand out as odd. So even if there is no expert on breasfeeding living in the house, at least most women in a relationship would have a competent house-keeper.
The other thing is that, due to the fact that breastfeeding has never been lost, there is far less crusading about it, it is far more relaxed. When I gave birth in the UK I was surprised at the fervour with which my decision to breastfeed was greeted. To be truthful, it made me feel a bit stressed, as if I had just announced my intention to do something brave and unusual, run a marathon or something. A midwife went round the beds in the ward and asked all the mums how they intended to feed: the ones who said bf were greeted with a beaming smile- and the rest were not. It made me feel uncomfortable- and I had never considered not breastfeeding in the first place.
Hard to avoid the crusading tone in a country which does so need to promote breastfeeding, but it can add to the pressure.