Steven Pinker, the famous linguist who isn't Noam Chomsky, doesn't think using "literally" figuratively is all that bad. "The figurative use doesn't mean the language is deteriorating," he says in a 2014 interview, comparing it to the hyperbolic use of "terrific" or "wonderful".
Photo by jmm
"But 'literally' is a special case!" you might be ready to comment. "It has a concrete meaning defining truth value," you might add. So did plenty of other words. The word "fantastic", for example, first meant something false or imagined. Over a couple of centuries, it gained the metaphorical meaning we usually think of today: "Very good." But while someone might whine that it's overused, no one still complains that "fantastic" should only mean "fictitious".
It's understandable why people do it. We are always in search of superlatives, of ways of impressing upon our hearer that something that happened is noteworthy or even extraordinary. And the words we use to signal that eventually lose their meaning.
Of course, it's much easier to live with a word such as "fantastic" when everyone already agrees on the new meaning. While it transitions, "literally" loses some of its usefulness, which is a pain in the arse.
But there are plenty of other terms -- there really, actually, factually, in fact, truly, truthfully are -- to convey the same meaning. And human communication involves tools such as context and tone that help us detect irony, informality and generalisation. Of course, all those tools can be flipped too -- a deadpan delivery is irony dressed up as sincerity. But that's what we get for ever crawling out of the sea and trying to relate to each other.