Tell your boss to lower his profit margin to 2% and see how that goes.
Ebay fee percentages do not represent or equal their profit margin.
Clearly they're related, but their profit margin from the ebay service is the total that they get from those fees minus the costs of developing, hosting, marketing, and providing support for their service.
Someone needs to start a new eBay of sorts. I don't mind them making a profit....but it should be clean and simple. A flat 2% fee of sale price is fair. Everybody wins.
My understanding from a quick google search is that about $60 billion a year in goods flow through ebay. 2% flat fee would give them about $1.2 in revenue. Turning to their income statement, their annual revenue over the last 4 quarters is reported at $11.6 B. Their net income is $3.2 B, so (simplistically speaking...some of this is accounting) annual expenses of various kinds are $8.4B. The income statement numbers include all sources of revenue at the corporate level (including PayPal), but clearly $1.2 B in revenue from their main business line would not be anywhere near enough of a contribution to cover their expenses.
Now, this is a simplistic look. They have other sources of revenue and other lines of business beyond eBay (most notably PayPal). And the question of whether their expenses are anywhere near in line what it should cost to run an auction site is totally different topic. But what is clear is that a flat 2% fee would not work for them the way they operate now. Could they be more efficient? Probably. Could someone start up an auction site that runs more efficiently and can be profitable on 2% fees? I don't know. If it were that simple, I'm sure someone would have done it and destroyed ebay by now.
Don't get me wrong though...I really do think eBay's fees are pretty high. But the flip side can be seen in this thread. Craigslist operates with a vastly different and leaner model, and is free to use. But it has its own issues. Some of what you get through eBay, most notably the protection that is offered to both buyers and sellers, is worth something. Whether there's a middle ground option that would provide some of that for a lower fee, I don't know. I wish there was!