The main thing Etsy offers sellers is buyers' attention. My wife and I have sold on Etsy for almost 15 years (!!!), and she started selling from the first day she opened a shop selling bow ties. Over the years, it's very rare we'll open a shop offering something and not sell in the first day (and have never had a concept not have at least one sale in a week). It's hard to beat that kind of visibility with little to no investment honestly.

Even as our businesses have grown, the ease of use and convenience are hard to beat if you want to keep them to something casual. Sure, we could pop up a Shopify, ramp up advertising, really grind to get it "out there," but then we're spending more time and money to end up at the same spot.

A smaller marketplace won't have that sort of network effect. The only way I'd see it succeeding is if they really blitz on marketing and making themselves a real outlet for makers (and make sure they're perceived that way over Etsy). Their brand recognition and entrenchment would be super hard to overcome.