Err, if you read Stroustrup's Design & Evolution of C++, performance clearly was one of the primary design goals. Goals 2 and 3 in the statement you linked to spell that out. If a feature could not be implemented without effecting the efficiency of programs that did not use it, the feature was rejected. One of the points that Stroustrup stresses in D&E is that he wanted no languages below C++.

There are many features that do have a runtime or space cost, but you only pay for it if you use it. And I think that in many cases, what you end up implementing yourself would pay the same performance costs, if not more.