EMCAScript has an open standard that anyone can implement.
It's up to sites if they want to require an open standard and risk losing clients that haven't implemented it yet.
>churning constantly to anticompetitively maintain their monopoly.
Google open sources the implementations of these. Competing browsers like Brave and Edge are able to integrate this open source code to support them without themselves having to deal with constantly implementing new features.
Why don't you make a de-JSing Google proxy? Like SearX-NG?
Meanwhile Google actively blocks and attempts to pursue legal action against scrapers. Not to mention prohibiting it through TOS (getting your Google account revoked can be life-ruining for many people).