I like the model you are proposing but I believe there is more work needed around what you call “circumstances”.
If we consider the Bob Moesta/Chris Spiek interview technique a lot of what they are trying to expose is “circumstances”. To me this is the key to why 2 seemingly identical customers chose different products.
I believe that almost all “circumstances” are emotional in nature. “I don’t have the budget” usually means I feel like I don’t have the money. “I don’t have time to learn and use this product” is clearly emotional, etc.
What we need is a good behavioural/psychological model for “circumstances”.