In reply to Otto.

When I read somewhere online about a powerful theme like "Make" and then I hit the "Preview" button on https://wordpress.org/themes/make/ with all the hopes and dreams I have about my new site running on this theme and then I see this: https://wordpress.org/themes/make/preview/

I think we can all agree: that is a bad user experience. And I am not talking about the experienced WP user, he will of course download the theme. But for the average Joe the demo looks crap, and he will move on, probably to a platform that does a better job on showing him some nicer themes. When it was actually not theme authors fault, that the demo couldn't deliver, what he intended the theme to look like.

You are right: "Any theme should be able to handle a basic site correctly and beautifully.", but what about the theme that doesn't have blogging as its sole or main focus? The theme that uses plugins to handle all non-design aspects? Those themes, that leave plugin related features to plugins. These themes that can so much more, yet they can't show-off their true strengths by having only the blog home as a playground.

I don't know when exactly WordPress started to evolve from a pure blogging platform into a fully fledged CMS, but it has been quite some time. Yet, the way that integral parts of WordPress, such as "themes", are being treated and presented on .org, still very much mimics this "blogging" mindset from the past.