Where does this this linguistically phenomenon come from?

Is it a mistaken use of “an accident” with the preposition to reflect the personal involvement?

Mistakes like “Could of” make sense to me because in my accent “could of” and “could’ve” are identically voiced.

I can also completly understand where we get “alot” because alot is just the beginning of an acorn, minus a few hundred years of lazy pronunciation behind it (an oak corn =acorn)

Google is telling me it’s because younger people will use “on accident” as an antonym for “on purpose”. That sounds feesible as an origin. Now I’m questioning if “by intent” is grammatically correct, I’ve been staring at words too long.