I've bought spam while in muslim countries and for camping. But I absolutely do not see it as a substitute product for meat when times are rough. If it were a dollar can, yes, but as you pointed out, it's more expensive than ground beef of the same weight.
I guess it's mainly americans fearing having to actually cook something for themselves and stampeeding towards the convenience factor.

I hear you on making the massive pot of soup or stew. I love to indulge my hobo fantasies, too!