Companies in general rarely acknowledge where they really get an idea, since anything they do usually comes from a combination of ideas gathered over time; however if they were to acknowledge any particular one it usually causes someone to claim is their exact idea and of course they are entitled to being involved (aka entitled to being paid).
While on the subject, yes there is not a product today that can't be improved, since the bigger the company the more obtuse they become over time specially when too many positions get invented and filled with people promoted by the Peter Principle with cushy, but useless jobs to lose.
I am sure that anything posted here is read sooner or later by some smart person at Airbnb that recognizes it for what it may be - a smart idea.