While Clay Christensen's Jobs-To-Be-Done is brilliant, I think it's far from a methodology. Infact, I think JTBD is just another way of creating a Customer Hypothesis.
"People who use a product to do X job" is a Customer Hypothesis, and from there the Lean methods apply.
The key question is then, "What problem does the customer have in accomplishing that job?"
While Eric doesn't subscribe to the Customer-Problem setup (because of his background in gaming, which games don't really solve a problem per se). Problem can also be represented as a gap in the market or unmet need.