I would be interested in knowing if their tech could ever be phone-sized. It looks like focusing the light correctly on the sensor is more difficult than with a conventional camera ( their promo video looks to show about 8 lens elements). The entire design is basically a big lens with the sensor and screen on the back, that's why they adopted such a strange form factor. That said, there is significant variability in size with traditional camera lenses, so maybe once the market matures someone will figure out a way to produce cheap plastic light-field lenses.
As far as the high-fps goes, they use a standard sensor with custom microlenses. Procuring a new sensor, either for higher resolution or faster frame rates, is probably more expensive and less likely than continued software updates, and maybe even changes to the enclosure and lenses. I suspect sensor acquisition is a significant part of these cameras high price.