I’m not sure there’s much more juice to squeeze here via automated or semi-automated means. They could perhaps be doing these kind of human-in-the-loop reviews themselves for all extensions that hit a certain install count, but that’s not a popular technique at Google.

Chrome extension codebases are fairly basic, I think there's room to build an agentic code scanner for these, but the juice probably isn't worth the squeeze to justify for them $$$-wise. Manual reviews I agree are expensive and dicey.