Not really a concern? I don't agree. Look at large C++ projects, and let's not speak about GPU frameworks like CUDA, OpenCL and OpenACC. If it weren't be a concern, software companies wouldn't invest in clusters just for compilation.
Already in 1987 Turbo Pascal 4.0 was compiling quite fast, Borland states around 34,000 lines/minute for the 5.5 version in 1989.
Similar compilation speeds are possible for languages with modules, since the early 80's.
Go's compilation speed is only news for someone that never used a module based language for systems programming like Modula-2 or Turbo Pascal, just to name two.
We are repeating history because the old ways were forgotten or replaced.
Some Modula-2 compilers:
http://plas.fit.qut.edu.au/gpm/
http://www.excelsior-usa.com/xdsx86.html
Modern Turbo Pascal compatible compilers:
http://www.mikroe.com/mikropascal/avr/
http://www.embarcadero.com/products/delphi
It is just a matter to look for them.