I fundamentally disagree with your point that CSS-in-JS is a result of developers not knowing CSS. That's ridiculous
CSS-in-JS solves a lot of problems that people that have been writing 'real CSS' have been experiencing for a long time. Writing CSS for very large applications that deal with lots of shared components across engineering teams is a hard task. Some of those problems are alleviated by libraries like styled-components.
It's not for every use case and should only be used when there is a genuine need (rather than 'because it's shiny.') But shrugging off CSS-in-JS because you don't understand it is a bit silly.
CSS-in-JS solves a lot of problems that people that have been writing 'real CSS' have been experiencing for a long time. Writing CSS for very large applications that deal with lots of shared components across engineering teams is a hard task. Some of those problems are alleviated by libraries like styled-components.
It's not for every use case and should only be used when there is a genuine need (rather than 'because it's shiny.') But shrugging off CSS-in-JS because you don't understand it is a bit silly.