Doing nothing 10x as fast is not all that useful. In a real app it's unlikely the difference in context switching being 0.2% of your CPU time or 0.02% of your CPU time matters.

It's also not a fundamental restriction on threads vs Goroutines either. switchto is very nearly as fast a Goroutine context switching https://www.phoronix.com/scan.php?page=news_item&px=Google-U...