It did not fail for that reason, it was strictly economics. The Parachute CO project was going full blast ahead when oil was around $40.00 a bbl. IMO the project scared the living hell out of OPEC, the price of oil dropped to around $9.00 bbl. Blam and damn, oil shale was no longer profitably viable, end of story.
You’re right but it all boils down to how one defines “technology.” I was using the word in the broad sense that shale oil extraction technology is not presently cost-competitive with other methods of oil extraction. I probably should used more specific language.