I get that the main effect of a bad fuel pump is that the engine will cut out at higher speeds, and that this is often not easily noticeable until that happens because there are little or no prior indications that I am aware of. And that this doesn't mean that the car fails to start (in most cases). I also assume that the answer must be that for some reason it must be harder to maintain a good fuel pressure at higher speeds but I don't understand why.
Why is the effect of a bad fuel pump more noticeable at higher speeds?
Just to clarify, by "higher speeds" I meant an increase in miles per hour (mph) of the car when in motion.