Brooks dared to predict that thirty years later, software would still be created by programmers sitting in front of editors, painstakingly typing up code branches for all of the scenarios a given program is supposed to handle. And their output would still mostly suck, because of the infinity of possible states, mostly due to variables and synchronicity. Complexity that cannot be abstracted away.
Given how starry-eyed we usually are about even the near future, that is bold.
The web, language advances, tooling - these are quality-of-life improvements. They don't 'solve' the inherent complexity of software development, the way it was promised by CASE tools (Brooks' likely target with his essay) and countless other 'business oriented' approaches. In fact those approaches have failed so many times that they have been largely abandoned, so in recent times, Brooks' essay might seem superfluous.
The one advance that might finally challenge the 'no silver bullet' rule is machine learning. Not yet, given that it is still an esoteric tool for a specialized class of problems, as part of traditional software systems. But with increasing computing power, I can imagine a future where machine learning can be set to work on broader tasks and start to look like magic self-directed software development.