My understanding is that the injectors are positioned downstream of the throttle butterfly valve in the induction manifold.
So as you have said, there is no venturi effect on the fuel.
I also think that because the fuel is atomised by the injectors there is less of a temperature drop as compared to the vapourisation in the carburettor.
I'm sure an engineering type of person will know more about it.
Also I have a related question. Why isn't the fuel injected directly into the piston as in car engines?
FIS