That was absolutely not what was said. The way it was phrased indicates it only applies to a subset of projects, plus there were weasel words to indicate that maybe it's not actually quite that high, plus AI was not explicitly mentioned and it easily could include a lot of traditionally-generated code.
I ran across the dashboard where I work that is tracking Copilot usage. According to the dashboard 22% of suggestions are accepted. I assume Microsoft is quoting a similar stat. This is VERY misleading, as more often than not, the suggestion is trash, but has 1 thing in it I want for reference to look up something that might actually help me. I accept the suggestion, which increases that stat, but AI didn’t ultimately write the resulting code that went to production.
I took a glance around this project, and it seems to be really high quality Rust. I would be shocked if it was AI-generated to any significant degree, given my own less-than-impressive results trying to get LLMs to write Rust.
Edit: I see the author isn’t very familiar with Rust, which makes it even more impressive.
How much cost reduction does 30% ai written code translate to? It's easy to imagine that ai doesn't write the most expensive lines of code. So it might correspond to 10% cost reduction.
10% is nothing to scoff at, but I don't think it should factor into the decision to rewrite existing packages or trust third parties if you're very security minded.
AI-writing has the cost of human orchestration, debugging, review. Code is now cheap to write, but for there to be a net efficiency gain, those other tasks have to not bloat too much.