The author shared their experience building the first version in a month: https://themackabu.dev/blog/js-in-one-month

And then the follow up few months later: https://themackabu.dev/blog/ant-part-two

I'm not sure what the economics of building a new runtime and ecosystem from scratch are but it seems we're already in a phase where individual developers are creating software which previously took a whole team. And its only getting started...