FWIW outside the US in IPSC Production is the biggest division by far. While there are lots of Shadows and Tanfos there are a reasonanle number of other guns. And with our new rules I expect the other guns to gain in popularity at least a bit. That said there is a degree of fashion and follow the leader and if someone wins a world shoot or at a local level with a Arsenal Strike One or whatever you can expect to see an increase in the number of those being used.
I see the same in idpa. Lots of guys with Shadows who would've been better served continuing to compete with their G19 and learning how to shoot it better before they tried to buy skill