waterfall wasn't advocated because there hadn't been a movement for alternatives yet, it was just the default, like the iphone 2G, nobody called it iphone 2g wh

waterfall wasn't advocated because there hadn't been a movement for alternatives yet, it was just the default, like the iphone 2G, nobody called it iphone 2g when it came out, but in the context of newer models that's how we differentiate it