Would you consider LDPRELOAD a massive cost to Linux ? Because that's basically what it is.

You could give me the best kernel in the world, if I end up reading a file whenever I push a pixel to the screen, my performance will be dogshit. Windows's performance problems are not due to the kernel (or rather, not due to problems/bugs: some performance issues are just a choice. See NTFS's dreadful performance with Git: NTFS simply wasn't thought out for having thousands of very small files all being touched at the same time.)