Every time I see complaints like this I can't help but think the posters have a chip on their shoulder from being rejected by Google or a similarly selective company. It's never a commentary on any fundamental issues with these types of interview questions and no one ever comes up with a better process that is equally scaleable and effective for hiring generalists. In my experience interviewing with dozens of small, medium and large companies, the vast majority of technical roles require these types of questions now. These come off as criticisms against Google specifically for asking hard variants of these questions.
I don't personally have any issue with companies asking questions like these as long as they don't simply look for "a correct and optimal solution coded up perfectly whilst under stress in under 30 minutes", but rather the process of solving the problem.