Whether Leetcode is necessary can be discussed but this person doesn't add anything to the discussion. Almost disconnected 7 paragraphs of text and the conclusion is FAANG and S & P 500 needs to find a way to assess without Leetcode.
It clearly works for them so they continue doing it and able to grow their eng organisations to thousands of engineers. Any other solution to this problem wouldn't be without its trade offs. If he really wants to contribute to tech industry he is more than welcome to found his own company and hire the way he wants, instead of saying "I don't like this FAANG find a new way!".