>Go cares about scalability in the large

Which features precisely have led you to believe this? I can't see any indication of that anywhere. You seem to be creating a false dichotomy: "caring about abstractions and caring about scalability are opposing goals", so that you can ascribe one side of a nonexistent spectrum to go.

>But if you're not on a large problem, that 10% of repetition will chafe you...

Except that is simply not the case. The larger the problem, the more that duplicate code causes problems.