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.
Also, room and board are normally considered auxiliary enterprises, and self-funding. If they have profits, they contribute those to the university, but they are not budgeted with the general campus funds.
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.