Because it's hard. That's what kept me from doing it.
I am very close to explicitly starting a project to do just that, and didn't get to this point even until one of my powerful friends explicitly advised me to take a particular strategy to get relationships with more powerful people.
I find myself unable to be motivated to do it without calling it "Networking the Hard Way", to remind myself that yes, it's hard, and that's why it will work.
I would be interested in hearing about this strategy if you feel like sharing.
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.