The 32 H&R is one of my top few favorite revolver cartridges ever conceived. Low powder use, flat trajectory... a dandy of a small game cartridge. But it's never going to garner high popularity when compared to the 38spcl. Nothing will unseat the King any time soon - I think the 9mm would sooner be toppled from its throne than the 38spcl (because pistol shooters are far more fickle than those of us Luddites still hanging onto revolvers).
Is it just too similar to the really popular 38 Special?
The 32 H&R really isn't similar to the 38spcl outside of momentum and kinetic energy. The sectional density and impact velocity are very different, and the bullet diameter drives a decent spread in MANY of the stopping power metrics kicked around like Taylor Knock Out Factor, so what it does inside game is quite different as well. It's harder to find ammo for most folks, and often costs more since that ONE type of 32 will mid-level or specialty ammo, sitting beside CHEAP plinking 38spcl ammo. It's harder to find brass, which costs more, harder to find bullets, which often cost as much, and for most folks, one more round of "less impact" isn't compelling for most guys to "go out on a limb" with the 32H&R... When guys want something less than a 38, they don't look at 32, they go all the way to 22LR. When most folks go out after bunnies with a handgun, it's with a 22LR or maybe 22WMR... Not a 32...
I don't think the 32 H&R is going away, especially revitalized by the 327FM (which also won't ever win any popularity contests), but I also don't think either will ever garner a near-majority favor while the 38 and 357 are sitting at the table.
Consider the handgun buying market as compared to other firearm types. There are really very few options for revolver cartridges in its class - the 32/327 and 38/357 really are the only players at the table for the self defense revolver market. A few wild hair models are out there in 44spcl, 22WMR, and 22LR, but really, pickin's are slim. Alternatively, we have 22, 25, 32, 380, 9mm, 357sig, 40S&W, 45acp, 45gap, and 10mm in defensive pistols, before you make a huge leap up to the "magnum" pistol rounds NOT meant for defensive work. In bolt action rifles, there are HUNDREDS of cartridges in any given caliber or energy class. In shotguns, there's 410, 28, 20, 12, and 10ga... That's it... And nobody ever asks or cares that there are really only TWO choices in shotgunning...
So the defensive revolver market is a lot more like the shotgun market than that of the rifle. "Options" aren't really an interest.