It works fine in the lab, but there's a lot of engineering that needs to be done in order to scale it up to industrial levels. Some failures are going to happen along the way, and failures at that scale break companies.

That engineering only gets done is there's money in it - and oil's been cheap bar some temporary upsets. So the pilot plants were shut down or converted to biodiesel, which is much less risky.

Once the economics change again, you'll see movement in that area (assuming EV doesn't completely take over).