I don't think this person actually worked with CSS in the early days. The clearfix trick was back then, not now. It was back "in the day" that we had to do shitty workarounds like clearfix. Like CSS wasn't fun back then, at all. CSS wasn't fun, then not fun, and now fun again. CSS has been on a steady trajectory out of awful but it works, to predictability, and much more fit for purpose. React and the like have allowed for tight namespacing which makes collisions a thing of the past, and so the "cascading" element is less of a problem.