grammar - Is article and auxiliary verb omission in modern English an emerging phenomenon?

I am obviously not talking about newspaper headlines etc. in this question.

I tried looking it up online but wasn't able to find much. In many instances of spoken English (and, probably, making its way into written English as well), I notice people omit articles where they grammatically shouldn't.

An example from Daredevil which I just watched and remembered I've had this question for a while: "Kid's half an idiot! – It's the other half that counts." I'm positive you know what I'm getting at here. One could say "Dude is built like a tank" when the dude in question has been addressed already (and technically should have a "the" preceding it).
I have an intuition that the longer the phrase is, the less natural the omission sounds. For example, it's harder for me to imagine a phrase like "Dude flipped the table like it was made out of carton" without wanting to slap a "the" at the beginning.

I swear I've heard someone say "less you know about this, the better."

And finally, something that is probably the most widespread: dropping auxiliary verbs. It is so normal to ask a question like "sleep well?", meaning "did you sleep well?".

Yet, I cannot find any articles on this topic, and sometimes it makes me question whether I'm mishearing things. Yet, it is so widespread, there is no doubt it is a real phenomenon.

Is it a new phenomenon? Has anything like this happened before, either in English or in other languages? Are there any particular rules governing it?

Notes: