Everyone I know who has bought a house (not selling) has the seller pay the commission. I bought a house 2 years ago and the seller didn’t have a realtor, he paid 3% to my realtor. It’s baked into the price, you don’t pay $500k for a house and then add on 6% or 3% percent commission to pay the realtors. The commission comes out of the sale price.
I think you've missed the point of this comment thread. Head up to great-great-great-grandparent comment:
"IME this is one of the most common economic misconceptions that people have, to think that the economic cost of a tax is borne by whoever nominally pays it. Most people with no economics background will for example think that it's just companies that pay salary related taxes, or consumers who pay VAT. Those are both true in the accounting sense that the money is paid by those respective parties to the government but not in the economic sense of who would have the extra money if there were no tax."
Elsewhere in the thread is the example of credit card feeds which technically are paid for by the merchant, but economically are paid for by the consumers.
Now try to carry these concepts to your Real Estate Agent scenario. I shall leave that as an exercise.