While much of what we eat is American, there is still much of other commodities that is American made. Chevrolets are made here and lots of Toyotas and BMWs, too. Is it better to buy a GM owned car that is imported or a domestically produced Toyota? But if there is no car factory in the state where you live, you might say that all cars are imported but that begins to blur some lines and will make a convincing argument difficult.
Virtually all the comments made so far are mostly true but there is, as usual, more to the story. Companies were already relocating manufacturing ages ago to places with lower labor costs and that was just within the United States. Even when manufacturing was booming in some places, like, say, Maine, the manufacturers were importing people to work the factories. Hard to say why they bothered.
Traditionally the Republican party favored high tariffs to presumably protect American manufacturers, if not American workers. But the few times they had sufficient power in congress to do just that, American consumers did not like it. It drove up prices. And that was before the 1900. There's no reason to believe that consumers today would be happier or willing to be paying higher prices just to protect American jobs. There is at least one place I know where you can select an American made product over an identical imported product and that is on a website that sells work clothes called "All Seasons Uniforms." For Carhartt products, some are listed as American made and you can compare them with the same item imported, which are to be sure less expensive, although not a lot. That's price, not cost and I have no idea what the cost difference is. But they do have a lot of other American made products.
One problem that no one ever seems to want to discuss is that we apparently have no public policy in place to promote American made products over imported products or any kind of policy that is intended to address the trade deficit, which is the root of many (but not all) of our financial problems. But then, I suppose doing anything like that would be a managed economy or socialism or communism or some ism-or other that doesn't sit well with people. So this is what we get for it.