Speed of ionic reactions?

Why are ionic reactions extremely fast, as compared to other gaseous reactions?

The ionic reactions (precipitations, neutralizations etc.) are extremely fast (somewhere about $10^{12}$ times faster) than gas-phase reactions and other ordinary reactions in solutions (inversion, substitution etc). Why is this so?

My thoughts
One possible reason might be the relative freedom of steric orientation in case of simple ionic reactions as compared to organic reactions and complicated gas reactions, but this isn't the case with simple gas reactions or formation and dissociation of ionic complexes, which do require specific steric orientations. The activation energy could be very low for ionic reactions, if this is so, then what is the reason behind it?