Why they don't 3D cameras anymore?

A couple of years ago this Kickstarter campaign raised over HK$ 1 Million (around GBP 100,000, EUR 115,000 or US$ 135,000) for a simple 35mm film camera with three lenses, fixed focus/exposure and a built-in flash:

https://www.kickstarter.com/projects/reto3d/wiggle-the-moment-3d-film-camera-by-reto/description

It was designed to cash in on the recent craze for animated GIFs or wigglegrams (which don't need a special viewer), but shows that there is still some interest in this art form... and unlike some crowdfunded camera campaigns it actually delivered the product!

Heritage Cameras wrote:

...shows that there is still some interest in this art form...

I should have added that the older Nimslo and Nishika four-lens 35mm film cameras are often attracting sky-high prices on eBay.

Gerry Siegel wrote:

Taking 3D is supremely easy. Watching it has always been an obstacle. It is inherelty an individual exercise. When it was as they say a fad, there were complete systems that made it deliverable without a lot headache. If Kodak prints were tough to make or had to be sent off or were a pure hobby exercise--which 3-D Has become , it too would fade interest.

Kodak prints were tough to make, and had to be sent off unless you were willing to engage in a difficult "pure hobby exercise" for well over a century, and they didn't "fade interest".

The  MAIN reason that stereophotography has never really "took off" is not capture.

Capture is easy.

VIEWING is not.

There are too many viewing options, some work well, some not so well.