But don't count eBay out of the race to the top.
The company is partnering with Spring, a New York-based fashion e-retailer, to bring hundreds of big-name accessories and apparel brands to ebay.com.
Shoppers will now be able to browse the looks of David Yurman, Rag & Bone, Mango and Chloe on eBay's website, the same site that lets customers bid on toys, power tools and motorcycles. Like its retail rival Amazon, eBay's in the business of everything.
EBay's latest move shows the e-retailer is still trying to grow its online marketplace and shed from its image any perception of poor quality or too much hassle. Today, more than 80 percent of merchandise sold on eBay is new, and nearly 90 percent of items bought on the website are purchased without a bidding component.
It also reflects a bigger shift in the industry.
"The Spring and eBay partnership is evidence of a growing trend in which retailers are partnering — instead of competing — with other retailers," Jill Ramsey, vice president of merchandising at eBay, said.
"With Spring, we can bring even more coveted merchandise to our buyers, making it easier than ever to discover their own version of perfect."
The Spring storefront on eBay's website will function like a boutique, the companies explained, where shoppers should be pleased to find more of their favorite brands in one place. At least that's the goal, as consumers today are faced with more options of places, both online and offline, to ring up purchases.
"Spring's mission is to bring top brands to consumers at a variety of tastes, style and prices," Spring CEO Alan Tisch said about his company.
"Our new partnership with eBay helps further this mission and expand our reach," Tisch added. "Both Spring and eBay are committed to offering unparalleled selection across the best brands — including the newest, hottest styles, sold-out or hard-to-find merchandise, and great deals for every price and style."
Founded in 2014 by Tisch, his brother, David, and Octavian Costache, Spring's selection of products from more than 1,500 brands online today includes those by Michael Kors, Coach and Urban Outfitters.
Spring, though, has managed to curate an assortment of hundreds of fashion-forward brands, all within one site, and now it hopes to bring that same concept to eBay, making the internet marketplace a "dedicated destination" for women looking for Bobbi Brown makeup or a pair of Tory Burch sandals.
And both eBay and Spring agree that the more than 300 fresh brands coming to ebay.com should likewise benefit from the partnership. It's something that's expected to put their logos in front of more faces, maybe in front of some shoppers who weren't in the market for those products before.
As eBay's Ramsey pointed out, the idea of a big company deciding to partner with a niche name in the retail space is nothing new.
Wal-Mart has been on its own acquisition spree, buying e-retailers Moosejaw, ModCloth, Jet.com, and most recently announcing plans to acquire Bonobos. While its smaller competitor, Target, was keeping quiet for a while, the company last month announced plans to acquire a transportation logistics company to help speed deliveries. Target is also partnering with smaller brands to roll out exclusive products in its stores and online.
On Tuesday, Target announced its latest collaboration, with a couple featured on the home renovation network, HGTV. Chip and Joanna Gaines will be designing Hearth & Hand, an exclusive line of home and lifestyle goods, for Target stores and Target.com.
Amazon has indicated a similar interest in working with retailers, such as Sears and Kohls, to either sell the retailers' brands on Amazon.com, or work to get more Amazon-branded merchandise, such as the Echo, into brick-and-mortar stores that the internet giant doesn't have.
Tisch told CNBC that Spring will become more of a partner with eBay, and will help curate fashion catalogs for eBay customers ahead of the holidays. He added that in working with eBay, the two are sure to face more competition from Amazon in the market for apparel and accessories in the future.
But unlike Amazon, which has shown interest in rolling out its own private-label lines, Spring is sticking with growing its relationships with existing brand names.
On Wednesday, eBay's stock was climbing near 1 percent and is up almost 30 percent in 2017. The stock hit a fresh intraday high of $38.50.