As an out of stater, I'm kinda neutral..... When I think of trolleys, it's San Fran, then Ohio's Red Devils because of the race with an airplane. Interuban subways and els? Chicago & NYC come to mind, thats really about it though many others existed.
Mention of each area would bring these imediately to mind as part of the history and landscape...but with Boston mentioned, I just think of boats and U.S. History... eventually the B&M does creep in, but that's it. The fact it was also home to the first subway here doesn't sink deep because it isn't publicly boasted often enough, is my first explanatory thought.
We used to have a nice trolley system in Detroit before GM "helped us" with "electric buses". Honestly, that's what I see in the later equipment; electric buses; even on the ones with flanges. To me, they aren't really "trolleys", but the larger equipment that replaced the trolley.
In fact, in Detroit, it started with horse drawn omnibuses, and there were a few local lines, plus even the Red Devils for a few years to get to Toledo, Clevland, & Cincinnati. We had one of the first heritage lines in the 70s but it didn't do too well (on paper anyhow, the thing was full everytime I wawnted to use it. I usually ended up paying more and parking close to downtown because it was so busy.. again I'd bet the Auto industry somehow managed to ensure it wouldn't succeed or expand here long term)
( My great grandmother was killed by one of the locals when she lodged a foot between rail and pavement and the driver pushed through the crowd attempting to stop the driver...who just ignored them and sped up. On the bitter sweet side, Grandpa got to say goodbye just before his mom died in front of him...1918 or 1919 I think.)
My point is you likely didn't know about Detroit's systems because it was never publicly flaunted much because the "real news" here was only about the cars... the rest of the city's draws is forgotten or ignored since then; the same deal really.