Regression introduced in #9288
Raised in Slack: https://wordpress.slack.com/archives/C02QB2JS7/p1535356303000100 (link requires registration)

Steps to reproduce:

1. Navigate to Gutenberg > Demo

Expected: Demo content
Actual: Empty page

Slated to be fixed by #9403, but #9403 is a significant refactor that may require several iterations. A more immediate fix could be to revert #9288, while admittedly this regresses on the original behavior it was meant to address. Without #9288 and #9403, it is not immediately apparent how to address the original issue relating to our treatment of templates on initialization.