And that doesn't matter, because: - Such custom extensions live in custom extension space. - Software ecosystem that must work across vendors will use neither

And that doesn't matter, because: - Such custom extensions live in custom extension space. - Software ecosystem that must work across vendors will use neither. - If these extensions actually do something useful, the experience from them will be leveraged to make a standard extension, which will at some point make it into a standard profile, and thus adopted by the software ecosystem.