At what point do airbus try and re-launch the A380F?
Probably never. At least based on analysis I've seen, the A380 does not pencil out to be a good freighter, and loading freight on the upper deck would be problematic. Plus it would be near impossible to do a 747 type nose door due to the flight deck location.
What might work would be some sort of combi - freight on the main deck and passengers up stairs - but combis have fallen out of favor, and the latest regulations regarding cargo fire would make certification of a combi difficult.