From burrowing inside bathroom sinks to running between your legs as you try to walk, cats don't seem to mind invading your personal space. This is especially true for owners who cannot stretch their legs at night, as their cat occupies all the space at the foot of the bed.
Cats aren't considerate, but that's not the only reason they do it.
According to Vets Explain Pets, cats have a tendency to stay physically close to a sitter. If you are feeding them and taking care of their other needs, they will want to be around.
If this is true and no cat can confirm it, why not choose a place closer to you? It may have something to do with a pet's survival instincts. Having to get tangled in the bed or get rid of someone's arm is not a good situation for a cat who always wants to be ready to run. Being at the foot of the bed gives them freedom of movement. (It may also be why cats' tendency to avoid settling in or near stacked beds or blankets may be why they prefer kneading to be smooth.)
Some cats may also harbor a sense of responsibility over your well-being and may want to be around as a protective mechanism. They use it to be at the foot of the bed to control who enters the room.
Naturally, there may also be some selfishness involved. Being around a person who gives off their body heat at night provides a warmer environment. Although cats usually express their love by sleeping with you, it's partly for their comfort. And since cats are territorial by nature, their perspective on all this may be slightly different from yours. A cat may think it's sharing its bed with you.