There is piracy when you publish, I knew of Chinese & Russian copies of some of my commercial games, dunno if it was just "warez" or getting around Great Firewall.
In dev, you do sometimes get knockoffs but not often. A text adventure is hard to write, easy to steal the text of, but why? There's no money in it, and it's so personal a work. Graphics can be "worth" copying, but that's mostly from big guys like Nintendo, Sony, or SquEnix.
#gamedev