> Being a bit disingenuous, no ?

Not at all. If you pay attention to how people actually use the language, the word has both meanings, so either is correct. Such is the fluid nature of language. If you can't appreciate that, then I think you're very nice (in the original sense of the word).

Well, it would be nice if on the whole the fluid nature of our language added rather than subtracted. Allowing literally to add emphasis rather than being a statement of literalism makes it no easier to add emphasis but much harder to state something is literal in the classical sense. You are right that language changes and evolves, but that doesn't mean we have to passively sit by and watch it get worse.

That it makes it worse is your opinion, though. If the prevailing opinion agreed with you, the additional meaning of the word would have been unsuccessful. Nobody is using it because they're forced to; they're using it because it feels right to them to do so.

I don't think I've ever heard 150+ years called "the last few years" before.