I have a feeling that only a very small, select group of photographers make big money from assignments.
A lot of very talented photographers appear to earn a lot of their money teaching the rest of us how to take pictures and earn money

- especially in the Landscape Photography field. I read one photographers comment on how hard it was to get the right jobs, if you were not gay and had influental friends in NYC.. Probably half a joke, but it must be very hard to establish a business.
About your idea of motion blur for the background: Is there a place on the station where you can keep the model in fairly deep shade while keeping the background/passing people in brighter light. That should help reducing the amount of ambient light on the model, reducing possible blur ? Perhaps later in the day with less light through the glass roof...
Regards
Michael