I'm looking at an executable of a medium program I'm working on, probably around 5k LOC of my own code, using tons of standard library modules and linking to probably another 10-20k LOC of 3rd party libraries, all debug symbols in place. Weighs 5MB. I don't think this program in C++ would weigh much less.

Anyway it can be improved, but to me there are far more important things to be improved about Go than the binary size of small programs.