Nobility forbidding hunting and gathering is really more of a medieval phenomenon, and has much more to do with the nobility themselves becoming a large population and enjoying the hunt (and the meat that comes from it). If they didn't forbid it, it would be overhunted, and then those filthy poors would be enjoying the meat that rightly belongs to the bluebloods!

There's often, in early farming societies, a great deal of 'fluidity' between subsistence farming, raiding, and hunting-gathering. Subsistence farming dominates because of the aforementioned advantages, but a tribe engaging in subsistence farming might up and burn all their houses down and go on the warpath, or leave the fields unsown for a few years while ranging the local woods. The early Germanic tribes are a great example of this, both in the variation from tribe-to-tribe, and in the way they could swiftly change from one mode of life to the other. The demarcation is not all that 'strict' compared to later 'civilized' societies which are, themselves, mostly surrounded by other subsistence farmers (or pastoralists).

While farmer vs. hunter-gatherer has much more to do with the community choice than the individual choice, even in the most settled sedentary premodern villages hunters and gatherers both remain as viable - and often specialized - ways of life.

But yes, generally the success of the sedentary farmers is not so much conversion (though there is that) as out-competing the hunter-gatherers.