I was walking across campus with a friend and we came upon half a dozen theoretical linguists committing unprovoked physical assault on a defenseless prescriptivist. My friend was shocked. She said: "Aren't you going to help?"
“Literally” doesn't actually mean figuratively, even in use; it's used (figuratively itself) as an intensifier applied to some other figurative expression. This actually has the opposite effect to “figuratively”, which by explicitly stating that a use is figurative acts as a qualifier, rather than an intensifier, of the figurative expression it modifies.
> What's popular isn't always correct and dictionaries by definition reflect usage.
What's popular is correct by definition, that's why dictionaries reflect usage, they don't prescribe it. Language is about communication, not syntax, people do use "literally" when they mean figuratively and you know it, I know it, so they are communicating, the word has obtained new meaning. Words are not static things.
Some cultures put more emphasis on the top down approach than others. France[1] tends to be more into top down control of its language than the English.
In short: The dictionary isn't the "law", it lags behind the language as it is actually used. Once the "reverse" definition of "literally" became common in usage it became the new definition - not what a dictionary used to define it as.
That is unless it doesn't literally kill you that literally now actually means figuratively too.