If it wasn't for Nissan there wouldn't have been the Deltawing. It didn't have an engine until they stepped in.
The concept existed but yes it needed Nissan to make it a reality for 2012 Garage 56. It was brilliant, everyone loved it.
They then stole Ben Bowlby and took away their engines from the DeltaWing in order to create the ZEOD. The result was practically every supplier to DeltaWing jumped ship and they have floundered ever since, including fighting a legal battle against Nissan for stealing their designs. And then after all but killing the DeltaWing project in the states, Nissan turn up with their 2014 Garage 56 "don't call it a DeltaWing" ZEOD that wasn't the full electric car they had pitched, was hardly revolutionary considering the P1s on the track, and then lasted about 1 lap before it broke and they went home.
The DeltaWing was such a brilliant idea, and Nissan killed it.