Me too. The number of "revolutionary" designs that are announced but disappear makes me cynical. Looking wings on real aircraft, unless freshly painted, they're pretty close to finely sanded :) If the airlines and engineers saw a significant performance degradation with wear, they'd be out there polishing and repainting wings.

On a similar note - How many times have you seen announcements about someones blended wing that is going to save 50% fuel? But there are very few blended wings in nature (eg. rays), and those are in a very slow-speed regime.

The real obstacle to blended wing designs, I imagine, is more boring: airports are likely to be difficult to retrofit to support those, well for cargo anyways, and for passengers there's probably less appetite to board such a plane