What different metric do you think would work better? Github? I have seen people get job offers by taking someone else's project, editing commit history to make themselves the author, and then push it to GitHub and talk about that project in their interview. Sure, sometimes on drilling deep enough you would know people are faking it, but a lot of time people would pass through.
I just mean to say that all hiring criterion have tradeoffs, and none is strictly better than the others.