Cost has only really been an issue since the last great "shortage", prior to that, 357SIG was the exact same price as .40S&W when bought in bulk. Price is still pretty much even with most all of them when you compare premium ammo.
Reloading is just as easy as anything else, just one extra step with a .40 carbide sizer. With the right load, setback isnt an issue either. When I was first shooting it, the difference in price, about a buck a box of 50, wasnt worth the bother to reload. That changed as the price increased, although the price of components jumped right up there too.