I'm not going to try to assume where you are coming from on this subject but I will offer the way I see things.
Honestly- I can't wax all philosophical about how everything I do leaves a print on something or someone either puposely or indirectly. From my own point of view I have so many things going on in my personal realm (which no one is interested in hearing about) that I can't afford to lose the few precious sanity points I have on thoughts as you posted above.
Not to knock what you initially wrote- it is thought provoking and maybe you'll get some good convo out of it.
I don't think it's egotism that gets in the way of these deep thoughts- I think it's the fact that alot of us already endure some sort personal suffering and really can't afford to suffer for the world as well. I think it's great that there are people out there who devote their lives to the military, global ecology, veganism, disease research, rocket science, feeding the hungry, dog grooming, etc. Who give up everything to persue these passions- but it takes a special kind of person to do these things- and I am not one of them.
I'm not heartless, it's not that I don't care, I do care. Plain and simple I'd be wearing a jacket the buckles up the back, rocking back and forth in a padded room if I tried to seriously contemplate all that is worng with the world and how my personal sacrifice could make it better. My view on this is strictly self preservation. But kudos to you in any case.