Chaosmancer
Legend
Because everyone else is growing trade crops with adequate yields to allow for profitable trade.
When you're growing food for self sufficiency and based on personal preference, you can afford to be less efficient in your fantasy botanical pursuits.
But to your point, other similarly self-sufficient and insular communities could exist if they're not particularly interested in accumulating wealth. And.. they may not make for particularly attractive raiding targets.
They would of course be less lucky and typically less good at hiding, and so some amount more likely to get raided than a comparable halfling village.
That makes no sense.
If it is a plant, it can be grown. If it can be grown, it can be grown in quantities for consumption and trade. Somehow these magical spice plants can't be grown in enough quantity for trade, but they can be grown to support an entire village's needs? No. That isn't how growing plants works.