The only thing that has changed as of this vote of the three things you listed is the "stability" aspect. Maybe that is sufficient to cause an exodus, but I am not sure.
The perception of London being the doorstep of the EU has just changed to London being outside of the EU, it would make zero sense for the EU financial center to be technically outside of it.
Stability plus the fact that Frankfurt is already a major financial hub, and that Germany is a major driver of the EU economy.