- Many older cities have street layouts that can best be described as a cluster-f*ck (while the reasons they came to be likely entirely make sense, an outsider presented with a map of a typical older city center will only see overlapping spider webs), so surface transit (buses, streetcar) may not be the most efficient mode. Subways that can simply go under the whole mess will have a better time of it, as will bicyclists and pedestrians.
- After WWII, at least in 'Merka, world+dog embraced The Car as the new Light and Way, and city planners laid out burgs accordingly (with more than a little help from the automotive, real estate development, and other parasitic interests): offices here, commercial there, industrial way over there, and residential in protected glops separate from anything vaguely noisy (as commercial areas are wont to be). Since, the assumption goes, everyone has a car, what's the problem? Now we know that this deeply segregated style of planning is not the most efficient way to lay out cities (while keeping heavy industrial away from neighborhoods is probably a good idea, residential can generally co-exist with office, retail, and other light commercial usages as many older cities can proudly attest), and forcing citizens to own, feed, and maintain vehicles (meaning this money can not be put elsewhere into the local economy) SOLELY to get around because the city is not laid out to be pedestrian- or bicyclist- friendly is not sustainable.
- Some cities are trying to undo or mitigate this damage (infill residential development, repurposing former commercial space for live+work, laying down bike lanes on main thoroughfares or designating parallel side streets as bike routes, running "high frequency grid" bus routes so folks can have more efficient transit trips), but not all burgs will be able to do everything.
- I haven't heard anyone griping that the three lanes of road out of downtown are woefully unused in the morning and what dumb bunny put down "too much" roadway, or that since the roads are virtually empty between midnight and early ack emma some of the lanes should be torn up and replaced with sidewalks and trees. Why the kvetching when buses are running "too much"? Sure, there is probably room for efficiencies in ANY city's transit system, but a knee-jerk "empty bus= wasted funds" reflex is not helpful.
- Cars are just one mode of travel, among transit, bicycling, and walking. For many years, one mode (the car) has been exalted to the detriment of the others, and we now see some cities trying to undo the damage and better facilitate transport for all.