There's still someone mapping out the features, designs etc b4 the AI goes to create it. Also saying 30% of code was AI generated hides cost of making the correct input: Planning, already existing code, Testing & Feedback loop, Reviewing. Its like saying Roofers aren't needed because 100% of nails were done with a nailgun.
Some tasks are easy with AI, others aren't but even when the code itself was 100% autonomous AI generated, the features, design was mapped out by someone is probably sufficient to retain copyright.
An image created by a five word prompt does not have a creative depth in creation like an image created by AI but with many refinement steps to get something truly unique.