Revolvers are absolutely more popular in areas where ammunition capacity is restricted. 7 round .357 is a great option in areas where there is a 10 round max for magazines.

Places out east (NY, NJ) have extremely low limits for capacity, both in effect and proposed. When ammunition capacity is reduced, there is an incentive to go for a (typically) more reliable revolver. Many people would rather have say a 7-shot 357 S&W wheelgun vs a 9-round (maximum) semi-auto magazine.

I ankle-carried a .357 snub for most of my life, and it literally weighed less than the 5 rounds that it held.