While it's true that eBay pivoted to a more profitable niche, their original niche was still quite profitable: they were a successful IPO and pulling down cash back in the days when most sellers were regular people. So if they're abandoning that market to focus on a more lucrative one, it might [1] leave an opening for someone else to focus on it, and make good, even if not eBay-sized, profits.

[1] With all sorts of uncertainties I haven't properly investigated, such as whether there's been a significant shift that would make old-ebay-style auctions much less profitable today than they were 10 years ago.

Since this is meant to be HN:

There's a lesson to be learnt. If you want to build a niche, build one that anyone can access. Better still, build a niche which stops people being locked out. Later on, you can screw the unwashed masses, and turn it into a B2C channel. See - Youtube, eBay, the iApp stores, the internet in general.

Yes, really.

Keep in mind a LOT has changed since the beginning. When eBay did that pivot, there were far less options for small retails sellers to put their products online easily and efficiently.

Ultimately, I think it would be near impossible to serve both markets well. eBay certainly serves the amateurs poorly, so that area is ripe for competition (IMO). Maybe serving the "pro" market would be bigger overall, and maybe even more profitable, but an "amateur eBay" executed properly would make someone a metric fuckton of dollars.