Go doesn't pride itself on not having a runtime though. People aren't surprised that there's space taken up by the garbage collector and green thread management and such.
I don't understand your remark. To the contrary, a runtime should decrease binary size. The same PHP script (interpreted not JIT or VM'd though, obviously) will be only a few hundred bytes..
The runtime in this case is compiled into the binary. With php, the runtime is all contained in the php binary that runs your scripts, in Go's case, the runtime is copied into every binary it produces.
Aren't you just assuming the runtime is dynamically available? This is not a necessary feature of a runtime. You could compile PHP and add the size of the interpreter to the executable.