As a professional poker player, analyst and journalist, and being fairly well-read on classifications of gambling vs skill game in different jurisdictions, I have not before come across a definition of gambling that was rooted in the idea that "no good or service is being produced."
Any zero sum or negative expected return conctract would meet this definition (quantitatively). if it floats your boat (makes you hallucinate etc), of course that might be considered a good or service. so you're right, if I was a lawyer those words would be loose language.
