Fundings more complicated then purely patient turnover. Every patient has a set funding level but this changes depending on complexity of the patient.
And for every patient I have who complains about the food I have at least 2-3 who smash all of it. And your not cooking for 100s, try 1000s! Do that on a limited budget, meeting huge range of requirements (changes in salt, protein, potassium, energy, fibre, texture, shit we have a diet for low iodine.), ages and cultures.
And dietary requirements don’t always get you a better meal, it’s all cooked at the same place. Plenty of people complain about our special meals.
Nutrition is certainly looked at (it’s apart of the accreditation for hospitals). No one’s serving you food you hate on purpose.