If X amount of people consider Y to be a large sum of money and Y is required to run a node, then obviously people from X won't be running a node. I'm not sure why you posted a map of the nodes though. As for that $30 example, take a look at any country where the minimum daily wage is <$1.
So people living on <$1 a day will never run a node, not even if we cut the blocksize in half.
Further, those living on <$1 a day have less interest (or use for) bitcoins than they do for 20% discount on Bentleys or Panamanian shell corporations.
These people are not a part of the Bitcoin ecosystem, certainly not as far as nodes are concerned. So why are we even talking about them?