Take a look at Jarred's twitter, and you'll see he spends a lot of time profiling things:

https://news.ycombinator.com/item?id=31993429

Of course, I can't say for sure that he looked at the fastest possible way to parse json here, but my intuition would be that if he didn't, it's because he had an educated guess that it'd still be slower.

That's not logically connected to statement "parsing JSON is major bottle neck".

It's just comparison of execution times of several different package manager.

Better would be parsing JSON vs binary in Bun.