The EMdrive is still being worked on. There are private, and secretive, efforts to develop it, in addition to NASA research at Eagleworks. They're building test apparatus which eliminate any possibility of error from gravity, heating, etc. But they're working with very low electrical power, so the thrust they're dealing with is miniscule. There's a theory that thrust is not linear, and that the maximum efficiency is at an electrical power of 50kW, and that it's a LOT of thrust. My *hunch* is that there are groups working with EMdrives which are tens of kW, but not superconducting (but as high Q as a room-temperature RF cavity can get)...just to see what happens. Working with superconductors is difficult and expensive. The commercial superconductor industry is developing MgB2 technology for high-field magnets used in MRI, fusion, and particle accelerators, and once some of this fabrication expertise is gained, I believe that we'll see EMdrive using it. I'd give a rough estimate of 4-5 years. I don't see hi-temp (cuprate, etc) superconductors in this application for some time.
The revolution of a practical EMdrive will disrupt the propulsion industry, which may be one of the reasons NASA is putting such little money into the projects which are the subject of this article.