If Amazon, eBay, and Etsy are the most successful eCommerce websites, why not build a Shopify store that looks and works like them?

I wouldn’t try to create a marketplace, and that’s also why I wouldn’t design a store that looks like Amazon, eBay, or Esty, etc. Marketplaces are super difficult to create, and that’s why there are so few of them. If you’re a talented and lucky merchant, your store may become a thriving marketplace one day, but you should start by building a small brand, a niche store. Focus on a specific niche.