My view settings were set back to defaults, of course, and changes made to Image View were still saved, but the program simply didn't remember that I was last in List View. Tried rebooting, just in case.
So I completely uninstalled LaunchBox, deleted *everything* in the LaunchBox folder, rebooted, and reinstalled with all of the default settings and directories.
Even before importing any games, I tried switching to List View, closed and reopened LaunchBox. It was back to Image View. Nothing changed once I imported some games.
Is it possible that defaulting to List View is something that's only available in the paid version?