To the best of my understanding, the removal of the stairs was actually part of the Brooklyn Bridge access program of the mid-20th century; Robert Moses used the 'City Beautiful'* rationale to sell the idea. The theory was that it would enhance the triumphal arch of the Municipal Building. (That's where the City keeps its dumpsters today. Yesterday's triumph. Today's trash. I think there may be some symbolism there. )

When I first arrived in NYC, I had a part-time job working for the Municipal Archives of the City of New York. The Building Department delivered their old records to the Archives by dump trucks - vast quantities of historic blueprints, files, and documents. The Buildings Department crew simply made a series of 10'-15' high mountains of the material in the middle of the courtrooms of the Tweed Courthouse. My job was to sort, file, and register the materials. The basic task was repetitive, but the materials were a treasure trove. Whenever I got bored with the sorting and the filing, I took time to review the documents. What a treat! I learned a great deal about New York with that job.( Justin Ferate)

*Generally stated, the City Beautiful advocates sought to improve their city through beautification, which would have a number of effects: 1) social ills would be swept away, as the beauty of the city would inspire civic loyalty and moral rectitude in the impoverished; 2) American cities would be brought to cultural parity with their European competitors through the use of the European Beaux-Arts idiom; and 3) a more inviting city center still would not bring the upper classes back to live, but certainly to work and spend money in the urban areas. From City Beautiful: The 1901 Plan for Washington D.C.