That doesn't strike me as a problem. It models what consumers actually do. The consumers are still being fed and they're suffering only a minor loss in their preference.
They don't keep any kind of hedonic measure, which might be interesting. If a consumer would rather have steak, but switches to chicken when it's over $10/pound, and then switches to tofu when chicken hits $10/pound, they're considerably less happy even if they're reasonably well fed.
You could probably use that to calculate some kind of hedonic metric: "I was originally willing to pay only $1/lb for tofu because it brought me 20% of the pleasure that a $5 steak would have." But you're not 80% less happy overall, since food is only part of your total happiness, so you'd need a "basket" of happiness.
They don't keep any kind of hedonic measure, which might be interesting. If a consumer would rather have steak, but switches to chicken when it's over $10/pound, and then switches to tofu when chicken hits $10/pound, they're considerably less happy even if they're reasonably well fed.
You could probably use that to calculate some kind of hedonic metric: "I was originally willing to pay only $1/lb for tofu because it brought me 20% of the pleasure that a $5 steak would have." But you're not 80% less happy overall, since food is only part of your total happiness, so you'd need a "basket" of happiness.