I don't really know what an oyster bed is.
I don't disagree with you philosophically, but to carry your argument to its logical conclusion, there would only be one offence of theft. It wouldn't matter whether it's less than $5,000 or more than $5,000, whether it's an automobile, whether it's a testamentary instrument—it wouldn't matter. That would be to carry your argument to its logical conclusion—one offence, theft, with one maximum penalty.