The cache files are not deleted if the cache folder if created manually, that's right, but, each time the game is started, the cache files in that folder are modified, which seems to indicate that the cache files are generated again, even though they exist already. So it is kind of pointless to even create the folders manually.
Topic on Talk:Wolfenstein: The Old Blood
I think I noticed that before. First of all, the statement about the game regenerating the cache for each session if the folder is not created might be just incorrect - the cache may not exist at all if the folder is not created. That's why people still report the option as helpful for fixing some stuttering. The note you mention is the same since RAGE was released, and might be just obsolete.