If fast food becomes too pricey, people will go back to making meals at home - duh!
You forget all the Gibsmedats who don't even know how to cook food at home nor do they care if the fast food charges they put on their SNAP/EBT cards add up.
When their free credit card runs short, they will just agitate the politicians for more because they "need" it for their "survival". The politicians, naturally, will cave and keep buying them off with our money.