Okay ... sorry for my bold expressions.
But expecting a 1:2 breakthrough in lossy still image compression sounds like a miracle to me, if I do not even expect that to happen in video compression.
Even more than the "revolutions" (e.g. something else than DCT windows) which happened from MP3 over VQF and Vorbis towards Opus in the audio world.
Something that might come at least close was V-Nova, the "noise modelling" in video compression, similar to mp3Pro and HE-AAC.
_
P.S.:
Wavelets instead of DCT was most probably not the expected miracle. At least not on its own...