Room and board costing more than tuition is not a new thing and I doubt amenities is the whole reason. I went to a state school over twenty years ago and room and board cost more than tuition. It was hardly amenity-rich: most rooms were doubles with a shared bathroom down the hall, no carpet, old worn furniture, and no air conditioning. The food was cafeteria style where fajita night was a big feature. The rec center was considered glorious but was funded by a separate fee of about a hundred bucks a semester.

I suspect room and board costs what it does compared to tuition simply because putting undergrads in a big lecture just doesn’t cost all that much. In addition, the tuition for resident students gets subsidized, while the room and board generally doesn’t.