system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why haven't we all been sucked into a black hole by now?

Shouldn't black holes get more and more dense with every thing they suck in?  Shouldn't this lead to more gravity and thus more things being sucked in which would lead to more gravity and....

edit: Maybe I should clarify, it seems like the effect would be exponential growth, and over billions of years it seems like there should be some black holes that have collected entire galaxies by now.  Also, maybe explain it to me like I'm 10.
gpt
Imagine you have a star. Now imagine there's an imaginary sphere around the star that's the size of the star. When the star collapses into a black hole, imagine that imaginary sphere is still there (representing the star's original size). Even though there's a black hole at the center, outside of that imaginary sphere it will not exert any more gravity than the original star did. 

**tl;dr: A black hole won't "pull" any more than the original star did, unless you pass within the space the star used to occupy.**