Interstellar shows us that the main sources of food on Earth are being slowly wiped out by a disease they called The Blight. The solutions they try to enact are 1. to grow more food to make up for what's lost and 2. to leave Earth.
- to grow more food to make up for what's lost
- to leave Earth.
But why not just cure The Blight? If it's incurable (even though they have decades to work on it) it's a big enough problem that you could justify using techniques like Hydroponics/Aeroponics, isolating the crops from others, or GM, modifying them to make them resistant to it.
Did I miss something saying why these techniques wouldn't work?