Blended wings are more beneficial when it comes to fuel efficiency increase and noise reduction. However, no manufacturer has decided to produce these airplanes for major airline operation so far. What are the inhibiting factors in the industry for not using this configuration?

From what I can guess:

* It is a complete new configuration with low experience on it. High risk.
* Aircraft will be in VLA sector (>500 passengers), a sector not very attractive nowadays.
* The 90 seconds evacuation limit needs to be observed.