The most "compelling" argument I've heard is that while there's no net increase in quality or innovation, the value unlock is that a tiny number of people can produce the same software as a large number of people previously. Allegedly, a single engineer could launch a startup and put out a great app that would have taken a team of dozens (hundreds?) in the before times.
I don't buy that at all, but that seems to be the main selling point at the moment.