I’ve written about Core, Near-Core and the Outfield.
There will be scope creep. And the Definition of Core will continue to develop. With usually longer enterprise sales cycles that can be a problem.
Ask your salespeople: Why are we in this account?
This is especially true with Near-Core opportunities: There will be a class of prospects where you are the last straw. They are terrible businesses, they should not be around anymore, they have no sustainable advantage. They have tried everything, they have screwed up every partner or supplier relationship, and now they come to you. You are not a good fit. They often try to repurpose your solution into something else that you don’t want to be. You might be tempted to think “well, maybe that’s the golden goose, maybe that’s a new area that I have not thought about.”
Being open-minded and humble is great. You are supposedly experts in your field and in your industry. Could you perhaps have overlooked this opportunity? Could you perhaps been wrong about the buying motion? Could you perhaps been so focused on a particular problem because of your experience or position in the past that you were blindsided on more pressing needs?
I would suggest you run it by the board once you have several inbound requests like that, once you have more data and fewer anecdotes. Have that discussion every quarter. Unless you have run a process and changed the definition of what’s core, ask your salespeople on a regular basis: why are we in this account?