I was in the neighborhood the weekend it opened and strolled through. Thing that struck me was that there was no seating almost anywhere. People were sitting on the floor and it felt like a weird refugee area.
A lot of public-facing plazas are meant to be ornamental or monumental and nothing more, which is quite sad.
https://www.pps.org/article/wwhyte
He literally filmed what people actually did in public spaces, and came up with great guidelines to make them enjoyable.
Architects study this is school. As you say, whenever it isn't implemented, it is because they specifically chose not to, not because they don't know better.
The plazas at Herald Square and Times Square also have limited seating, but there the main limit is space.