How about power levels equal to, or better than 38+P for $5 LESS per box of 50?
Guns are extremely traditional, the majority of us standardize, we conform to the safe and well established ways, it makes sense in for many reasons, it takes a large advantage in something new and different to overcome this tradition inertia.
and for handguns the tradition, the standard is:
Rimmed cartridges in revolvers
Rimless cartridges in autos,
yes you can use moon clips, most of us consider them an unnecessary complication when they already make cartridges made to properly fit revolvers.
for me .38 is a range only cartridge, mellow recoil, mellow bass report, a higher pressure cartridge is not desirable here, 9mm will not make any different hole in the paper or soda bottle, tin can, to spend $500 to essentially duplicate what I already have with more hassle? yea the $5 savings a box might be nice but it will take years to pay back, $10 a month vs having some other interesting new gun that fills a real usable niche in my safe? no contest.
For defensive revolver where more pressure is desired 9mm is not enough above .38 to really warrant wasting my limited gun purchase on it, SO I bought a very early 586 in .357 a truly great fighting revolver cartridge.
the inexpensive, ubiquitous, compact, but anemic, and foreign 9mm does have its place though, it makes a wonderful compact, flat, and light single stack Tupperware for concealed carry, and If i want to shoot 9mm that is what i will shoot it in, I can always use the practice.
There are some of you who want to go against the grain, that's great that is how new good things are found. after the path is found to be safe by paving it with your money us sheep will follow. but it is the bleeding edge and some things tried don't really make sense so they are not widely adopted. 9mm revolvers are one of these failures, gun history is filled with them.