I think more powerful tools yield different apps, not just the same apps in less time. Because of the process of human design, I doubt we'll have solid, robust, lasting apps built "in a matter of hours", but potentially more and better version 1's.
Development aside, designing, testing, marketing, etc. seem to take a certain fixed amount of thought, discussion, and reflection. So it might still take a few weeks or months to build a great app, but in that time, you could experiment more. Going from, say, days to minutes to build certain features would be incredibly valuable. You could try things you never would've had time for otherwise, and end up with apps that wouldn't've even been possible with other tools.
Development aside, designing, testing, marketing, etc. seem to take a certain fixed amount of thought, discussion, and reflection. So it might still take a few weeks or months to build a great app, but in that time, you could experiment more. Going from, say, days to minutes to build certain features would be incredibly valuable. You could try things you never would've had time for otherwise, and end up with apps that wouldn't've even been possible with other tools.