I think this might be Shopify's play, at least it would be what I would do if I was them. Enable high quality sellers to have their own branded website to sell

I think this might be Shopify's play, at least it would be what I would do if I was them. Enable high quality sellers to have their own branded website to sell their own product directly. Then make it easy to find the Shopify sites via some general search or directory. You're able to slowly build up power this way without it being too obvious, and you provide an immediately valuable service to sellers that aligns incentives from the beginning.