More recent market studies have shown more interest in the .380 then the .32, I presume because potential buyers are repeatedly told that "bigger is better."
For some that's true, but for others it isn't. When individuals with no experience go to a retailer, gun show, etc. they seldom get a chance to try out various handguns, and tend to get whatever is recommended. If it's a very small, lightweight, straight-blowback .380 pistol they may quickly have second thoughts after actually firing what they purchased.
I personally think that a mid-sized .32 (think of the Colt model 1903) was introduced it might eventually become a good seller, but it's unlikely that any of the larger manufacturers will try it. As it is they can sell all of the .380's they can make.