It’s not so much that the bar should be higher, so much that leaving the bar as low as it is provides a signal that contrasts the range of sky high standards New York also makes possible in other ways.
Yes, the subway sucks, but New York’s tendency is to let the full scope of humanity simply exist out in the open, as is, warts and all. This is the philosophy I take away from it.
Should the world standardize a mandatory minimum quality upon public civic spaces? If we did, wouldn’t that require cracking down on deviations from the prescribed norm? Wouldn’t that drive people out, possibly sending some to a place much worse that a dirty smelly subway tunnel? The answers to these questions aren’t cut and dry.
Secondly, there are plenty of cities with clean, "quality" civic spaces that are also have plenty of weirdness and colourful culture, including Berlin, Paris, Barcelona and Moscow.
I'm in NYC, and the subways may be powerwashed now and then, but I have to side with the parent here: They do still routinely smell. Not just the stations, either. It's a common sight, even during rush hour, to see cars that are completely empty except for a single scruffy-looking person with plastic bags for shoes; there's a reason nobody else goes into that car.
I'm from Scandinavia, and this summer I traveled back with my American girlfriend. She couldn't get over how clean and tidy everything was. Not just the cities and roads, but also the subway stations and trains: No cracked tiles, rusty beams or random brown water dripping from the ceiling, or puddles of mysterious green matter; modern signage, electronic boards, elevators, escalators; digital ticketing; and so on. The trains zoom in almost silently, and the cars are spacious and comfortable. She said she felt like she'd traveled 20 years into the future.
While you can talk about economic factors — budgets, age of the system, etc. — my thesis is that it also comes down to cultural differences. Scandinavia isn't just clean because of wealth, or a smaller population; it's that cleanliness and tidiness is part of the culture, and it's strived at almost subconsciously at every level, from the individual to the government. That only works thanks to the homogeneity of the population, where everyone share approximately the same values. NYC certainly is not like that.