Honest answer: Because that sounds terrible.
I'm not going to waste my time cooking food that I won't eat at it's prime, just so it can take up my fridge space until I inevitably ruin it with a microwave later in the week.
Also, storing and reheating good creates MUCH more potential for contamination and food borne illness.
I can pay for my lunch with the money I make in the first half hour of the day. It's not breaking the bank.
"NOPE! I WAS WRONG! THE PANTHER IS DEFINITELY EATING ME! STILL REQUIRE SAVING OVER HERE! HELLO? ANYONE?"