Obviously when you're on a small hub with 3 other people in a coffee shop, the amount of traffic is small and it wouldn't be too difficult for a hacker to sort it out; whereas someone trying to eavesdrop on the traffic on a fiber optic cable downtown has a much bigger challege.
Quite opposite - bigger traffic - more opportunities to steal. The difference is on other side - it is pretty hard to eavesdrop on fiber cable, and extremely easy on unencrypted WiFi. It was not a real problem when technology was available to serious guys only: we are too small for them. Now it became available to anybody...
