The author's point is that adding some technologies such as JS sound like a good idea because at the beginning they are used reasonably, but they then get abuse

The author's point is that adding some technologies such as JS sound like a good idea because at the beginning they are used reasonably, but they then get abused. Encouraging better design and graceful decay didn't work, because it was too easy not to care. If you want good design to be the majority, it must be the path of least resistance.