I don't think your books will balance. There are not enough billionaires to find this. Also, they will all disappear, I bet they have good lawyers.
And I bet if implemented that threshold would come down and down and down. Let's talk to a prosperous Ukrainian farmer in the interwar period. Sent to a goo-lag for having a sewing machine perhaps?
i smell double bind. say nothing and the food is taken away, with parents being forced to spit up more money for food. say something and rich people will be sad, which means no money added to pay for food, which will be used to justify taking away the food anyway.
what's your solution then? you may not need the government to pay for your kids' food, but there are people who still needs it. you gotta feed people somehow and be careful not to fall into ableist policy (e.g only people who quote unquote, "works hard", gets the food).