We are a fad driven industry.

They could have rewrote it in java in a similar amount of time, and with the same results. And they could hire from the large pool of expert java devs. Of course that's not "cool".

It would not have solved the deployment issue. It is very nice to only have to deal with dependencies once, when building (when using go). In java, you have to deal with both build time and run time dependencies. It's really nice not having to lug around and package up a jvm, jars, ...

Each java based microservice requires its own packaging of jvm, jars, etc. Without this it is not easy to replace individual microservices, as the cross dependencies between the microservices will take away a big advantage of going that route.

Go provides this level of deployment separation for free by default.

Problem is I don't know Java. But I know enough Java to know that it will take lot longer for me. And I might not have simple deployment benefits, thats important feature of Go.