a local farmer had 100 hives in his soy fields. He told me bees can give him 3 - 4 extra bushels per acre. So they are at least a pollen source.
in my knowledge soya is self pollinating.
Many crops and fruits are self -pollinating.
But is has been shown that additional pollination for these crops does increase yields many times up to 10% as compared to no pollination.
For some crops like self-pollinating fruits trees, where they will be thinned anyways, no farmer is going to pay for an extra 10%. I'm sure the soybean farmer will not pay either for a few bushels more, but he will see an increase with pollination.
Self-pollinating fruit crops may also see a better uniformed and developed fruit with honey bee pollination.
So lets not discount pollination even on crops that could, if need be, go without pollination. Honey bees give in many ways even when we are not paying attention.