Before leetcode, we had people asking puzzles which had nothing to do with your coding abilities, like "How many balls could fit on a Boeing 747" or "If you have 9 balls, a see-saw, and one ball weighs more/less than the others, what is the minimum number of weighings to find said ball".
Alma matter also used to matter a bunch more, and non-traditional schooling devs were much harder to come by.
Leetcode isn't perfect, but it's better than what we had before. That said, I don't think it's the "final form" or optimal template for interviewing. What I would love to see are more constructive suggestions for objectively evaluating candidates that don't devolve into things easily bullshitable or biased.
I don't think the certificate days would be much use today, given how fast frameworks change and just how many different technologies are involved with modern development.