Go development is fast, because the language is simple and it compiles very quickly.
Once you've made it, you certainly don't want to recode. Although, of course, if you've super-made it, you can just get more hardware. But even the largest web companies can run into the performance bottleneck. Like Google, apparently.
The Go Authors say one of the motives for building Go was the very long compile times of building C++ apps for large-scale web development. One thing they mentioned in particular was the large compile times due to processing and reprocessing of #include files. We know Microsoft ran into the same problem because they put Pre-Compiled Headers (PCH files) into their C family tools. Go has an import facility that prevents the problems of the #include file design.
Go is trying to hit the sweet spot for large-scale development. Go is by no means the only one, of course.
Any of you guys know how well .NET does in compiling big web-scale applications? I don't.