We can rather tidily solve this by saying orthography and writing systems are artificial methods of representing the spoken language which have prescriptive rules. English spelling certainly shows that it's not difficult to retain many spellings that no longer accurately reflect the pronunciation of the word, if they ever did in the first place. On the other hand, preventing grammatical changes or semantic shift in words over time is impossible. Nobody's ever managed that (perhaps we could find some exceptions among languages that are used in religious or ceremonial contexts primarily and not as someone's regular means of communication).
It's a distinctive feature of English that spelling and pronunciation are only loosely related. It's because of the history of the language; and of the country, for that matter.
This is a completely different example, as this is only a spelling mistake/difference. When these people write "break", they clearly mean "brake". They are not adding the meaning of decelerate to the verb that means to tear into pieces.
The evolution of writing is separate from the evolution of language in general. Read and read are still different words even if they are written the same. If the spelling "brake" for declaration fell out of favor and "break" was used for both words, this wouldn't change anything about the English language. The two are already homophones, and they would be far from the only homographs in English.
I actually think it’s close enough that they could be mistaking the root meaning; think of ‘break’ in terms of elemental forces - a windbreak, a breakwater, a firebreak - think of how ‘taking a break’ is slowing down, is decelerating, is ‘braking.’ Breaks slow the movement of energy through a medium. Brake is a pretty easy mistake to make if you’re not sure which is which.
When some say "I laughed so loud I literally rolled on the floor", they do not, in any way, mean "I laughed so loud I figuratively rolled on the floor". Instead they mean "I laughed so loud, that it was almost like I was literally rolling on the floor". It is merely used as a generic augmentative: the phrase has the same basic meaning with or without "literally", but it gains more emphasis with it. The fact that it happens to apply to a figurative usage of "rolling on the floor" is mostly a coincidence.
Its just like "very" (which is a contraction of "verily", truly) has been adopted as an augmentative and lost its original meaning of "truly".
But no one uses ‘using “literally” to mean “figuratively”’ to literally mean ‘using “literally” to mean “figuratively”’, either. Instead they mean ‘using “literally” in the context of a figurative usage’, as you point out—the censure of which is warranted by its being a lazy cliché. The augmentation is not generic; the coincidence is feigned in the service of irony.
Lots of people do use literally, which manifests by them complaining that it is becoming a self-antonym or that it's losing its meaning. Is it a lazy cliche? Probably. Is that a reason to complain it's hurting the word literally? Obviously not.
Should we accept "break" to mean deceleration, or as a noun for the equipment to slow down a vehicle, then?