It seems to be dying off here a bit. The idea never really made a lot of sense in our climate- where gearing down becomes actually a safety matter.
I did see one very interesting fixed about a week ago with the single free-wheel on one side, and a "locked" hub on the other. Huge single chain ring- the largest I've seen in street use. He was riding it on the freewheel side and using the single rear brake.

Someone else mentioned the over-priced stuff not moving. I agree with that completely.
See a lot of stuff on f/b and other buy and sell sites that simply does not move at all- to the tune of years.

-D.S.