Comment by _bent
Lytro light field cameras. The tech was impressive and the company was able to put two products on to the shelves, though unfortunately they hadn't quite reached the image quality needed for professional photographers.
But now with the new Meta Ray-Bans featuring a light field display and with new media like gaussian splats we're on the verge of being able to make full usage of all the data those cameras were able capture, beyond the demos of "what if you could fix your focus after shooting" of back then.
Beyond high tech, there's a big market for novelty kinda-bad cameras like Polaroids or Instax. The first Lytro has the perfect form factor for that and was already bulky enough that slapping a printer on it wouldn't have hurt.
The problem with the Lytro was that the sensor/lens pair was just too darned small. If they had somehow scaled it up so that the sensor was about 4" in diameter, even if it meant using an interposing frosted glass plate or something to allow a smaller image sensor, the depth of field effects could have been fantastic. It would have allowed genuine and beautiful bokeh across almost any arbitrary focal plane, even pan/tilt, in software.