Amoeba:
Okay. Burglary was a bad example on my part. How about someone who is emotionally abused (in whatever manner) day in day out by their spouse as a form of deliberate 'attack'? Slowly but surely they'll get used to it. The spouse will simply continue it. Don't get hung up on this one example, btw. I'm sure there are other such examples that can be thought of. I hope you get the gist of what I'm trying to say.
From hadith, we know that bad dreams
can (may not always) be from shaytan. So with that in mind, you could also ask, going by your current mode of reasoning: 'I have had bad dreams so often that they don't affect me anymore, why would shaytan persist in doing this?'. The answer to that from me, would be 'I don't know'.

This doesn't mean there isn't a proper answer for it, just something I am personally unaware of.
Shayateen/jinn consist of different species and what motivates them
Allah knows best. These beings have crude personalities and are said to have low intelligence, from what I understand.
You're free to believe what you wish, sister. I personally will not attribute sleep paralysis to a natural bodily function. Just my belief based on what I have experienced and read of over the years.