We know a lot less about hunter-gatherers than most people think, and hunter-gatherer tribes fluctuate a lot in terms of their diets/lifestyles, as one would expect with the diversity of the world.

Vegetables tend to be low calorie, so you wouldn't expect tribes to expend a lot of effort getting them. That doesn't really apply to a modern environment where getting enough calories isn't a concern and vegetables can be bought at your local supermarket.