Seems to me David Braben still likes to ride on that wave of past success.
The problem I see is that the gamers that used to play Elite are slowly but surely growing out of playing video games altogether. Back then he didn't have the means to create a AAA title, now he does, but space games have been relegated to a niche market over the years which have too little ROI to be worth the risk. It looks very unlikely that Elite IV will ever get released.
I look forward to DNF though, whenever it does come out.