I thought I was getting better results earlier.
C2 in chrome:
60fps till 800
60fps till 2900 with the "for each" disabled
godot:
60fps till about 800 as well.
I think what's being measured from this is the speed of events or gdscript.
Looking at the bunny mark here:
https://pixijs.github.io/bunny-mark/
I get 60fps up to 5900 with the chrome
and this:
http://www.goodboydigital.com/pixijs/bunnymark/
gives me 60fps up to 20,000. I guess js isn't actually that slow?