I do recognise that a lot of it is probably just playing up for the joke, but I assume it has to come from somewhere. I regularly see posts where basically Person A sends an odd image/message, then follows up with “wrong number, sorry” and Person B responds with “wait stay”.
Do Americans, as a rule, not save phone numbers? Or is it purely a bit that has become a trope?
The “wrong number sorry” thing is a joke. The joke being that the person intended to send that absurd image to anyone at all.
It’s basically just “meme fluff”; Low-effort padding around an actual joke in order to draw attention to the joke for people with short attention spans. Same as those “who did this 😂😂😂” things, or when people put “nobody: / X:” or “pov: XYZ” or “X isn’t real, X can’t hurt you” in front of an image. It doesn’t add anything. It’s often just done to freeboot a meme without it being detected as a repost/stolen content.