The Web 2.0 concept, which was mainly just marketer-speak for using a lot of AJAX, survived and continued. Agile survived but was transformed into its own opposite. Rails continues, but it has lost its ability to draw newcomers, which was its source of vitality. This is not because the technology has changed, but because the world around it has changed.
In a lot of places, learning Ajax was synonym to learning Web 2.0.