In the timeline's way,yes you're right.But however,the concept
of the RSQ was meant for the movie I,Robot at that time and not
intended for a future sport car.The R8,as what you've said,was
based on the RSQ but still has some of it's root in the current
generation - the petrol engine and the "regular" door that
is.
But however,since the movie I,Robot take place in 2035,the car is
then designed as futuristic as possible,so IMO i feel that the RSQ
should be the successor of the R8(and no longer the concept car -
production car it be).Reason being that R8 has some of it's root in
the current generation("regular" door,petrol engine etc)
whereas the RSQ is totally revolutionary.