9x19 is weaker out of short-barrels on little revolvers like the LCR and it still recoils painfully for most people. It compares to 38 Special, but can't even come close to 357 Magnum unless the Magnum is loaded down or with fast powders. A 2" 357 can send a 125 gr. bullet over 1400 fps, but it better be out of an N frame snubby or there will be pain.
The more it is pumped-up in a lightweight gun, the more it needs a crimp and bullets with a crimp groove and 9x19 doesn't.
In big revolvers like the 929 and Super GP-100, 9x19 can and does do very well, but those guns are primarily popular with competition shooters who pay a lot for an edge that casual range shooters don't need and that are impractical for people to use for carry.
The 9's short case is well-suited to fitting inside a pistol grip, but this feature is irrelevant on a revolver. The short case length is an advantage in ejection and reloading, but this has low relevance outside competitions involving reloads, or law-enforcement duty-guns where revolvers have been thoroughly retired.
The reason 9mm has greater availability and lower price is not because it has greater availability and lower price. The reason is that people are buying far more guns in 9x19 and shooting far more ammo in 9x19 than anything else. This is a demand-driven characteristic of the market. It is not driven by the supply side. If people started buying more guns in a different cartridge and buying more of those cartridges and creating more demand for those cartridges, the supply will increase and prices come down. It seems unlikely that will happen for 357 or 38 or that it will happen for anything specific to revolvers. The best chance revolvers have for a revolver-cartridge renaissance would be some kind of cartridge that fits in an outside-the-grip magazine. Take 300 BLK for example. I'm not saying it's good for revolvers, but it came on the market relatively recently and it really stormed the market with its price-per-round simultaneously plummeting. 30 Super Carry was a recent challenger to 9x19, but it looks to be fizzling. It wouldn't be better in a revolver, though cylinders could be made with one or two more chambers. 327 Federal didn't really take off either.
The 357 Maximum was once a popular revolver cartridge for metallic handgun silhouette shooting, and it is very, very close to the same dimensions as 350 Legend (also now a revolver cartridge). It could be that the "next big thing" for DBM's will also be a great revolver cartridge.