Imagine the market power an UPS or FedEx would yield if one of those would command the biggest marketplace in a given country as well. This is what Amazon is building, coming from a different starting position.
But not everyone can build that.
Etsy on the other hand is showing what else marketplace companies can do. Build additional marketplaces that are closely enough related to the established marketplace to get network effects to kickstart the new endeavour (and, of course, have it meaningfully connected for this purpose):
“Our 1.7 million sellers are able to create jobs and incomes for themselves and build value in their communities, connecting with 27 million buyers all through the Etsy platform. […]
Etsy Studio, the first new market we’ve built from the ground up since Etsy.com debuted in 2005, will be a global market dedicated to craft supplies that seamlessly combines inspiration and shopping in one place. When it launches this spring, visitors will be able to shop original DIY projects and tutorials alongside all of the supplies they need to bring those creative projects to life. […]”
Essentially, every new thing Amazon is building today as adding marketplace businesses to the portfolio: Subscribe With Amazon, the Treasure Truck, Prime Now, Amazon Business, etc.
Etsy Studio leverages all of the considerable investments Etsy has made in its technology stack over the years; search, discovery, checkout, promoted listings, machine learning, and more.
Etsy Studio launches with over 8 million items, compared to something like 200,000 to 300,000 at a typical craft store.
In addition, Etsy Studio features project-based shopping.