It's hardly selective to note that the overwhelming majority of metro systems across the world have mobile signal underground. New York is an outlier, just like London, in not having it. Being one of a couple of stragglers is hardly a strong argument that it's not necessary or valued.
New York seems to have had people in charge that weren't so interested in investing in public transit, hence it starting to fall apart. Maybe with the congestion zone and a new Mayor, they'll be able to bring it up to modern standards. Good public transport in a city has huge economic benefits.
