More pressure, same weight = more velocity of course.
Why are revolver cartridges classically longer than typical modern auto ammo such as 9mm?? It has to do with design of the time, metals used in construction, and powder available at the time.
As to popularity, no clue. I think a 9mm revolver is cool. and some are making units that can shoot both.
Smokeless powder invented 1884.
38 special invented 1898, developed from parent case 38 long colt, first produced 1875.
9x19, first produced 1901, developed from 7.65x21, developed 1898.
The 38 case was developed from the 38 long colt, originally loaded with black powder. Case volume was necessary to accommodate the requisite charges of the day. (38 special holds 21 grains of BP but my present day light reloads are only 4 grains.) In modern times, that excessive case volume is one of the challenges with getting repeatable accuracy (at the bullseye level) out of light loads - you have no control over how the powder "lays" in the case.
Semi-auto rounds (notably, the 45 ACP and other surviving cartridges from the era, like 9mm) were developed to be shorter because John Moses Browning and his contemporaries wanted to magazine feed through the grip, not broomhandle mouser style. There's no way to fit enough black powder in these cases to get the job done. Smokeless powder was a given for firearms designers of the day - Browning, Mouser, etc.
The difference in 38 special and 357 case volume is minimal, yet 357 cases having higher pressure capacity, and can thus be loaded well beyond 9mm. Point being, the volume of the 38 special cartridge is a vestigial aspect of the cartridge.
At the heart of this, smokeless powder allowed for smaller and higher pressure cartridges that opened the door for semi-autos as we know them today as opposed to many of the anemic rounds of 100+ years ago. 32 special, etc.
In modern times, a 9mm revolver that uses moon clips can be a very practical shooter...if your armory has lots of 9mm already and you're interested in adding a revolver for novelty/training sake. That said, if you're into reloading, there are piles of 38 special brass around in the basements of widows who's husbands are no longer PPC shooters. It's an easy round to reload and lever action rifles are fun.
In either case, a 3" barrel IMO is insufficient to realize performance out of any round, but the 3" gun in my pants is better than the 4" gun left in the car.