You can push the logic even further : as even sustaining your body in a small tank becomes unsustainable, one might really go all virtual : get rid of your body, and upload your mind in a piece of silicon (or whatever replaced silicon). The silicon would be much less expensive to run than your meat brain.

Even if you don't believe your upload wouldn't truly be you, you might take the option, if the alternative is certain death by starvation. Better die and spawn a ghost, than die and leave nothing.

Now it's not all pretty: if you assume a capitalistic, competitive environment, one could set up "interesting" forms of exploitation. An upload could be saved, stopped, restarted, spied on, tortured… Robin Hanson produced quite interesting (though horrifying) speculation about how such a world might look like.