There is an enablement requirement. The patent has to be able to teach a " person skilled in the art" how to use the invention. You can't patent 3d printed food

There is an enablement requirement. The patent has to be able to teach a " person skilled in the art" how to use the invention. You can't patent 3d printed food without disclosing how to do. But the strategy you suggest is sort of used. The patent attorney will keep open an application for years using procedural tactics, and then try to get claims focused on modern products into the patent.