It is already - in the my opinion deeply silly book/movie series(?) Mortal Engines. I haven't read or watched them but saw a video ad and thought that it was the stupidest thing I had ever seen. Anyway it is effectively landships except they are massive steampunk mobile cities which grind up and harvest other sessile settlements and smaller mobile ones. I get the extended metaphor involved of colonalism and enrichment by exploitation of the weak and pillaging instead of their own production but even for YA Dystopian it is just too dumb logistically for me to suspend disbelief.