>Language evolves - things that start out as misunderstandings or errors become informal usage, then dominant usage, then the correct way.

Yes, language does evolve. For example, American English has evolved in such a way that "beg the question" now means "raise the question" to the vast majority of people in the year 2017.

Forgive me, but I think you're in the minority of people who bristle at the contemporary usage of this phrase, which makes you come off as incredibly pedantic.