Before I hire an artist that would make some graphics for me I would ask for a portfolio. Nobody in graphic industry is surprised when someone asks to show some of their works.
Same with IT, you would try to do some background checking. See if there was some recommendations from person's past employers or some sort of porfolio.
Should it be everything I would use to evaluate person? Hell no! But if I can see someone's actual achievements it gives me much more insight and confidence about how I am evaluating the candidate.
Would I miss some good candidates? Probably. But the strategy is not about not missing all good candidates, it is about ruling the bad ones. E.g. in Germany if you were hired, everyone though that you were ok, but then they found out that you are shitty, they cannot just fire you. They have to give you head ups that you are underperforming, then they have to make a formal evaluation to make sure that it isn't about them oppressing you and finally they are obligated to propose a recovery plan for you - only after you fuck it up the company is allowed to fire you. So you might end up with a guy not doing enything for 6 months. In such perspective it can be better to miss 2 good candidates than to hire one bad one.