This reminds me of the popularity of Rapid Application Development (RAD) over the past 15 years in languages such as c/c++/java, everyone thought it would mean we would no longer need programmers. In actuality, it makes the simple side of development really simple leaving the complicated pieces to focus on, if needed.

Will these tools put theme developers out of business? It will put the developers who could barely put a theme together out of business, which may not be a bad thing. The business of making sophisticated themes for specific clients will never go away. Thanks to WordPress packaging libraries such as jQuery, there's still an endless amount of opportunity for a developer to make themes that no automated system could replicate.

These automated theme builders will most likely slow down the growth of simple themes and make the more sophisticated theme systems that add additional functionality (such as Hybrid theme) more popular.