The largest tech companies could also implement a shared cert program via some kind of industry group, with periodic re-certification requirements. This’d surely be far cheaper than all of them running multi-stage leetcode and system design interviews, and they already basically publish study guides so this isn’t even that different, just cheaper for both the businesses and candidates.

It’d also make job hopping far less painful (see above: cheaper for the candidates) which is why they don’t.

So we may conclude: the point of leetcode interviews is wage suppression.