Your business degree is clouding your vision. Of course there is nothing at all wrong with your model but that doesn't mean it's the most profitable model.
My buyers of course pay all my fees, all my expenses in fact anything less and I'd be out of business. My buyers also pay extra, I run auctions, often they pay much more than "I want my profit to be" and when it comes to covering my fees if I can receive payment via a lower cost method then they "overpay" on fees. All this goes straight to my bottom line.
PayPal is convenient for sure but as I've said before it is the single most expensive way for me to receive payment. The difference against other methods can be as high as 10% of the transaction value, on cheap items the effect on the net selling price can be 15 - 20%.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
- answering Trolls is voluntary, my policy is not to participate.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
- answering Trolls is voluntary, my policy is not to participate.