Scoring in team sports most often succeeds if the defense supports the offense in a meaningful way.
When our team scores, everybody celebrates.
This seems to hold true for software development as well. A developer tries to play towards scoring. The tester aims at keeping the own end pristine.
Neither can succeed without the other. When the division of work is flawless, everybody appreciates, including the raving fans.
No team in the world can outsource success to a single group of experts. A team solely playing offense is sure to lose.