Go programs have roughly one active thread per CPU in the computer. I don't think they claimed they reinvented threading, they used a (known) model, where many

Go programs have roughly one active thread per CPU in the computer. I don't think they claimed they reinvented threading, they used a (known) model, where many green threads are mapped to hardware threads and added the primitives to the language. To make millions of goroutines on one machine feasible, they need small default stacks - 2kb currently.