Promotions would be harder - probably impossible - to anonymize, but at least you're working with a much, much smaller set of potential plaintiffs as compared to everyone who applied to the company. Anonymizing interviews is more feasible than ever, and it provides a very resilient defense claims of hiring discrimination. A straightforward way eliminate bias in orchestra auditions non-biased is to put a veil between the performer and evaluator. It's interesting to see proposals to do the same in tech getting downvoted.