[tedmiston]

It would be interesting to see data to support whether this hypothesis holds up.

I have two gut feelings:

1. Hobbyist Etsy sellers don't dedicate the time and/or lack the business savvy to be running additional sales channels outside of Etsy. Additionally, even setting up a Shopify, etc. store requires some technical ability that you or I take for granted.

2. Semi-professional Etsy sellers, for example, those coming from operating eBay or Amazon Stores, were already using their other channels before Etsy. So they were sophisticated enough that it was cheap/easy to have someone whip up an osCommerce + PayPal site for them. I did this personally for a few clients already successfully selling on forums between 2005-2008.