For those of us who understand python VM, i can tell you that Unladen was a buzz project. Its goals ("Make Python 10 times faster in 2 years by using JIT", etc) were absurd to the level of insulting the "people who know" (what is "faster"?, in which application domain?). Of course media and the readers cannot see the absurdity of such claims and went along to propagate it and crapflood all the news sites; sorry but unladen swallow was a huge title with the goal to make a big attention to the media and draw attention from other interesting projects at the time.
We had hoped its failure to reach the stated goals would be its punishment, but apparently anything that's backed by lots of money never dies:)
Unfortunatelly, i can't explain to simple people why this is the fact with unladen swallow here, and i neither wish to do so since this would be a waste of my own resources. People who like big announcements ("We shall magically transform python to 100x faster through the use of Dynamic Adaptive Just Before Time Compilation methodologies, within the next 4 years -- yrs Google"), please feel free to do so!