Another often unacknowledged reality about that - I suffered for three years in the "Salesforce" environment which bills itself as the be-all end-all "no more programmers" solution. In reality, it's clunky and limited, and even when non-programmers are able to get something that approximates what they want, it ends up being slower than molasses. That's when they call in a programmer to figure out what went wrong and it's usually something like re-running a complex DB query a thousand times to satisfy a simple request. And you can hardly blame the business users - they have no visibility into what they're doing, so it's completely understandable that they come up with an inefficient mess. If user-created software is ever going to be feasible, the back-end is not only going to have to translate their drag-and-drops into usable code, but it's also going to have to intelligently optimize: that is, infer what their goal is and find the most efficient way to achieve that goal. That alone should tell you how far we are away from a programmer-less future.

Aren't query planners already intelligently optimizing?

A lot of these optimizations have already been solved.