I don't see how they're better than a bus though. Both need to travel by road. Buses are just easier to swap out and replace as far as I can tell. Also you probably don't need a platform to board a bus.
It does seem to be almost some kind of stigma or classism with buses rather than an actual functional difference in technology. We have electric overhead-line buses and they're just the same as streetcars except you don't need dedicated lanes or putting in rails in the road (which are expensive, limit expansion, and present a real hazard to biking).
Have you ridden the bus in a major US city lately? Safety and hygiene are serious issues, depending on the city and sometimes the specific line. Despite owning a car, I used to ride buses whenever remotely feasible as a point of civic pride. That stopped after a number of encounters with other agressive, combative, smelly, and/or visibly ill passengers. This is all tied up with homelessness, drug abuse, and high crime in urban communities which political polarization has prevented the US from addressing. It's disheartening, as the economic and environmental advantages of public transit are numerous.
Okay but this is as fixable on buses as it is on street cars. Street cars may seem cleaner but I think it's because they are generally just kind of impractical for daily commuting and are sort of kept around as a tourist activity in some cities.
Yes, I agree that the problem is fundamental to both modes of transit. If street cars were more common, the same stigma would apply for the same reasons.
> does seem to be almost some kind of stigma or classism with buses rather than an actual functional difference in technology
I attended a talk on the effects of new bus versus light rail routes on property values. The fact that rail is fixed increases them much more. The switching cost is a feature. Nobody moves to a neighbourhood because the city opened a new bus route to it.
Something similar might occur with citizens’ give-a-shit factors. I get furious when my local subway station gets messy. I have no idea which bus routes go by. If a bus route became problematic, I imagine my neighbours would petition to move or cancel it before considering cleaning it up. You can’t do that with laid track.
You can look at it like this: a light rail line is a promise that transit will serve that area for decades to come.
And so when a light rail line comes through, the areas around the stations begin to develop, and quite rapidly, too. An example can be found here: https://goo.gl/maps/kEkn615bp5nUGVmv6 - that trolley stop was literally in the middle of an empty field when it was built, and there wasn't much around on the nearby roads, either.
A bus line gets added to where people already are, and can disappear as quickly as it came; there's no permanency.
The infrastructure necessary for streetcars naturally assigns priority to them on roads, demoting motor vehicles to waiting for streetcar signals and not the other way around. This grants efficiency guarantees assuming no sabotage.
