All were good ideas. And in all three cases, the proponents mistakenly thought they had a purity of vision and a style of programming that couldn't be emulated. Oh how wrong they were. You gotta keep it moving, you have to do more than drink the Kool Aid, you have to be creative about who you will work with, and you have to go where the market takes you. Luckily, we're seeing some of that happen in the open source world.
Open source is a major way to gather developer momentum.
All the specs in the world can't equal a piece of running code that I can copy and bake into my program. This is the programmer's way to build ever more complex machines. When an idea catches on, very soon, people want to tweak its functionality, get features that are only useful to them and perhaps a small number of people. Quark has its XTensions, for example, and around that idea a thriving market emerged. And Adobe Photoshop supports plug-ins.