Some things make them cheaper per linear foot than the same kitchen cabinets and some things pricier. The tendency for the drawers for bathrooms to be narrower, but have all the components of wider drawers drives the cost per linear foot up . The part that holds the sink is cheaper just like in the kitchen. Those tall sections are very expensive either way.

In general I would say expect the bathroom to cost more per linear foot. With the tall unit and number or drawers you have I say it probably applies to your specific case. The cabinets you had bid at that price should be fairly high quality,
I guess you will make sure you are getting your money’s worth on quality.