I really doubt spec driven development is gonna last. As before, creating working software and iterating on it is faster and makes it easier to understand what you thought you wanted but don't, even if it's vibe coded. So, hello agile, welcome back.
I think there is some good middle ground between spec driven development and iterations, like Compound Engineering. https://github.com/EveryInc/compound-engineering-plugin
The point is the agent writes the specs and the human reviews and revises or asks for another rewrite that takes 90 seconds or less. So specs are both cheaper and better than anything I've seen before. They still get a lot wrong and it is hard to review them very carefully, but its easier than reviewing code to suss out design intent.