Here is Ken’s 2/9/19 response: The default theme should have a single post template and should be more that adequate for most site. You should only need to create a single post template in elementor if you wish to display information in a way other than the way the default theme displays it.
We get very few responses on pcalr.org because we use posts only for news items so this is not a big problem, but it should eventually be fixed since lakekit.net has paid for the Elementor Pro version which includes the Theme Builder system. I found this related link. I currently am using a workaround of excluding any post with comments in the Elementor single template for posts.