> For example, making it slightly tilted because it was easier to draw on old screens.

No. Some older systems actually had straight pointers. The slightly tilted design is, I assume, a result of wanting to point to something while still being able to see what is to the immediate left of the pointer; useful for left-to-right text.

The best video on mouse cursors I've seen, by Posy: https://www.youtube.com/watch?v=YThelfB2fvg

It doesn't exactly answer the question, but I -- someone who doesn't watch video and wants text, articles -- have watched this video twice over. It's worth it :)