Nelson's inability to deliver a product, and use of his patent to keep others from delivering a product, might also have something to do with the idea not catching on.
Why does Ted Nelson need to deliver a "product"? He's not a computer scientist. He's not a product manager. He's just a goofy guy with wacky, interesting ideas. More of a philosopher than anything else.
From my point of view and as the parent said, the problem here was the patent and how that contributed to others not being able to deliver after a lot of work.